I just made my purchase. I need the sim card unlock code for TMobiles Sidekick LX 2009, so I can use my AT&T Sim Card

You can unlock the Sidekick LX from Jamica Network digicel using the Unlock code ,you can get the Unlock code within 0 to 5 Hours(approx) you can get the code at reasonable cost here Simpleunlocking.com and Unlock it ,then you can use it with any GSM Network Sim card....Follow the instructions below and Unlock it step by step...

Sidekick LX Unlocking InstructionsWarning : Do not enter any wrong unlock codes on your Sidekick LX mobile phones. If you enter over a certain amount of wrong unlock codes on your Sidekick LX mobile phone, your phone may get hard locked and sometimes become unusable.
1. Switch ON your Sidekick LX with a Not ACCEPTED SIM Card.
2. If your Sidekick LX asks for a PIN code, then enter your SIM card PIN and press OK.
3. Sidekick LX will ask to enter an "unlock code".
4. Enter Unlock Code we send to you.
5. Your Sidekick LX is now unlocked.

*NOT ACCEPTED : We mean, to use a Sim card from a network other than the network your Sidekick LX is locked to.

More than likely your contacts are still located in the old phone. Replace the Sim card back into the old phone and copy the contacts onto the Sim card, place back in your Sidekick and you then can locate your contacts.

It says just Network lock only,You need to enter the Code if it locked Network mean.You can get the Unlock code at here
http://www.superunlockcodes.com/sidekick-lx-2009/rs12wp9/ and Unlock it,get the Unlocking Instructions below to unlock it step by step.
Sidekick LX 2009 Unlocking InstructionsWarning : Do not enter any wrong unlock codes on your Sidekick LX 2009 mobile phones. If you enter over a certain amount of wrong unlock codes on your Sidekick LX 2009 mobile phone, your phone may get hard locked and sometimes become unusable.
1. Switch ON your Sidekick LX 2009 with a Not ACCEPTED SIM Card.
2. If your Sidekick LX 2009 asks for a PIN code, then enter your SIM card PIN and press OK.
3. Sidekick LX 2009 will ask to enter an "unlock code".
4. Enter Unlock Code we send to you.
5. Your Sidekick LX 2009 is now unlocked.

*NOT ACCEPTED : We mean, to use a Sim card from a network other than the network your Sidekick LX 2009 is locked to.
Each Sidekick LX 2009 mobile phone has an unique unlock code. You can buy the unique unlock code for your Sidekick LX 2009 mobile phone using the form above.

A request for a PUK code ("Personal Unlocking Key") will appear on your phone if your SIM card PIN code is entered 3 consecutive times incorrectly.

Your SIM card will then become "PUKed" or Blocked. This is a security measure to protect your service.

You need to call the Customer Service department of your cell phone provider and they will give you the PUK code which will unblock your SIM card.

When Unlocking, always use a unlock code - This method is the simplest and safest method to unlocking your phone. You can hook it up to servers; I would suggest code is if want to pay less (take the risk of trouble) on older models. New phones cannot be unlocked by software.
give your IMEI number & get the unlock code for ur mobile .......... you also get through online..........i will suggest the website Unlock-Zone.com/ which is doing good service .....you can approach this website.

follow the directions

T-Mobile is usually pretty good about unlocking the SIM to different regions if you are a customer.

I had them unlock 2 cellphones for me simply by calling their customer support line, and informing them that I travel very often over seas and require my phone be unlocked for use in other regions.

once it says to enter your "special code" you hit cancel and it enables the sim pin. then you go to change sim pin, put in your old sim pin and put in a new one. then go to network settings and select "scan and select manually". once you find at&t click done and you can use the sidekick.

just ask the phone company provider for your PUK2 AND PUK codes.
when you get them go to the jump menu dial
**05*PUK*passcode*passcode#
the passcode is any 4-8 digits you'd like, that are NOT, AND I REPEAT N - O - T consecutive.
(for example 2736 is good whereas 1234 or 9876 is bad)
if it asks your for the code again put in the PUK2 then go to settings> network options goto the "scan and select manually" button and chose your carrier.

works for sk 3, slide and lx.
the video says only at&t in the U.S. but... i've seen it work for fones in europe.
try it.