How did you do it?
click here for a guide if you used fdisk.
Boot with XP CD if you used XP and choose the option to partition.
Do you have an OS installed now? If XP, right click on "my computer" and choose manage, then disk management and you will see the disk there. You will be able to format the remaining partition and thus have two disks of 30gb each.
Please give more info about your hardware / software.