I recently updated my ibooks app for the iPhone 3 and now it will not open. Any suggestions?

You can directly delete books from your iPhone in the iBooks app. Here is how:
Step 1. Find and open the iBooks app on your iPhone.
Step 2. Click on My Books at the bottom bar. Click on Select on the right hand corner, tap on the books you want to remove.
Step 3. Click the red Delete button to remove books in iBooks from iPhone.

Purchasing ebooks through the iBooks Store is very similar to buying any other media via Apple's iTunes Store. One key difference, though, is how you access the store. Rather than through iTunes or a dedicated app like the iTunes Store app on the iPad and iPhone, in this case, you access it through the iBooks app.
In the top left corner of the iBooks app is a button that reads "Store". To access the iBooks Store and begin shopping for iPhone- and iPad-compatible ebooks, tap that button.

Once you enter the iBooks Store, the browsing and searching experience is very similar to using the iTunes Store. In this case, you can search for the author or title you want in the top-right corner search box.
To browse books, either tap the icons on the main page of the store or tap the "Categories" menu item in the top left corner. This drops down a menu with all of the iBooks store's categories in it. Tap the category you're looking for to see books in that genre.

In the iBooks Store, when you tap a book title to get more details (synopsis, reviews, etc.) a window pops up and the background grays out a bit.
In this window, you can download a free sample of the book to your iBooks library by tapping the "Get Sample" button. This is the equivalent of iTunes' 30-second song preview, which helps you get a sense of whether you want to purchase the book.
When you decide to purchase a book, tap the price on the left side of the screen next to the book cover. The button will turn green and read "Buy Book". Tap it again to buy the book.
To close the pop-up window and not buy the book, simply tap anywhere outside the window.

You buy at the iBooks Store using the same iTunes account and password as you do at the iTunes Store or App Store. When buying a book, you'll be prompted to enter your password to pay for the ebook before it will begin downloading.

Once you've entered your iTunes account password, the eBook will download to your iPad. How long this takes will depend on the book (its length, how many images it has, etc.).
When the book is done downloading, it will appear as a title on the bookshelves in the iBooks app. Tap it to begin reading.

Are you too young? Are you older than 13? And if you are older than 13, are you over the age of consent in your jurisdiction to form a binding agreement?

From Viber's End User License Agreement:

18. Acceptance of License. You affirm that you have the ability to enter into this License. If you are under the age of consent in your jurisdiction to form a binding agreement (and you are more than 13 years of age), you affirm that you are either an emancipated minor, or possess legal parental or guardian consent, and are fully able and competent to enter into the terms, conditions, obligations, affirmations, representations, and warranties set forth in this License, and to abide by and comply with this License. The Service is not intended for children under the age of 13.

1) you need to be connected to the Internet
2) there must be enough memory left on the HD
3) for iBooks: the sync. must be on
Mac mini EFI Firmware Update 1 7

An Internet connection is required. On iOS devices such as the iPad, the iBooks App includes the iBooks Store. Tap the iBooks icon and your bookshelf appears. In the upper corner, tap the Store button and the bookshelf flips around to reveal the iBooks Store. From the iBooks Store, you can browse books by title, author, or genre. You can also view featured books as well as books available on the New York Times bestseller lists (United States only). Tap on a book to see more details and download a free sample. When you buy a book, it will automatically appear on your iBooks bookshelf.

Source:
iBooks Frequently Asked Questions FAQ about iBooks and the iBooks Store

Hope that helps!

The easiest way is to wait for a few hours and try to update your iPhone again. Best remember to try this way because sometimes it really works well. And simply, I would like to introduce the steps to upgrade your iPhone via WiFi environment first and foremost.

1. Open Settings of your iPhone.
2. Connect WiFi and find General on your iPhone.
3. Open Software Update.
4. The device would automatically check for update, or you could click the "Check for update" button.
5. After that, click Install Now button. Then you just need to wait until the update completes.

http://www.leawo.org/tutorial/what-to-do-when-iphone-software-update-failed.html

uncheck the sync books box in itunes. Then try to add them manually, if this does not work try the sync again after you have uncheck the box and applied the setting.

I had that problem, too and solved it by plugging my IPAD into my computer and updating it's software through ITunes...there have been a couple of updates in the last month and doing this solved my problem.
You first have to make sure you have the latest ITunes update and then it should find the software for your Ipad...which is actually quite a big download, so you have to be patient.
Hope this helps.

First delete all email accounts from your IPhone except the one that you want to be updated without opening the email app.  IPhone can only automatically update one email account without accessing the email app.  Under settings on your IPhone, choose "mail, contacts calendars."  Then choose "Fetch new data." Then make sure to set "Push" to the  "ON." position.  Then select the time window for checking for new emails, "15 min 30 min manually."  Theoretically, your email app will check your email account or new emails every 15 minutes if you choose the 15 min option. The IPhone does not yet update emails every time you receive an email.