I have a freeagent go 500gb portable hard drive. Is it possible to divide it into two 250gb partitions?how?

Of course you can. If you are using Windows Vista/7/8/2008, you can use windows built-in Disk Management to shrink the partition and create a new one with the unallocated space. If not, you need use third party partition software, like AOMEI Partition Assistant.
http://extend-partition.com/resource/how-to-make-a-partition.html

Yes it is possible. First you can use a partition software. The second is using the disk management tools, these are the steps.

1.To run Disk Management Tool, click on Start, right-click My Computer, and select Manage from the menu that appears. When you see the Computer Management window, click the Disk Management item listed underneath the Storage heading. You then see the main Disk Management pane in the right side of the Computer Management window.

2.Creating the partition: Unallocated space appears as an Unknown Partition in the Disk Management diagram, you can use it to create a new partition in some or all of the space. To create your new partition, you need to right-click on the part of the diagram that represents the unallocated space, the unallocated space has a black stripe running along the top and then choose the "New Partition" on the menu that appears. To create your new logical drive in an extended partition that has free space The free space has a light green strip along the top, right-click on the free space then choose New Logical Drive from the menu that appears. Now you will see the New Partition Wizard.


The Partition Wizard will asks you to specify the following:


1 The Type - Primary, extended, or logical partition. Your hard drive can contain up to four primary partitions, or three primary partitions and one extended partition. Choose the primary partition if you are created a partition in which you will install an operating system (this is unusual situation). Choose extended if you plan to create several logical partitions within it. The logical partition type is available only if you choose to create the new partition in an extended partition with some free space.


2 The Size - You may use the entire available space, or leave room for more partitions. The Partition Wizard will displays the minimum and maximum size for the partition, this is based on the space where it will be stored


3 The Drive letter or path - Two operating system on your computer. You may select any unused letter, but the wizard will offer the next available drive letter. To Mount in the following empty NTFS Folder, you need an NTFS partition with a drive letter on the same machine. You may select the "Do Not Assign A Drive Letter Or Drive Path" option, this will let Windows assign a letter later, usually the default drive letter.


4 The File system - The default is NTFS (recommended), but you can use FAT32 (not recommended) as well. Both NTFS and FAT32 will efficiently utilize disk space on large drives.
Note: NTFS has better security features, the better recovery capabilities after a major crash, and has file-level compression built in. NTFS will also give you the option of enable compression.


5 The Label - Type a name for the partition, name it something that will indicating what you will use it for, data files, my files, fatboy one, etc.

I hope this solution was helpful.