Dear Dev Juice,
I was in the Lion beta program. Now that 10.7 is about to release I want to reclaim the small partition I added to my laptop that I was using to test it.
How do I do this?
Assuming you did just that, you'll have a primary partition occupying most of your disk, and a secondary partition after that. Back up everything you can, especially on the second partition.
Boot on your primary partition that you have now updated to Lion. Open Disk Utility and select your hard drive (not the partitions under the hard drive) and open the Partition tab. Your layout should have the primary partition on top, the secondary below it.
Select the secondary partition and delete it by clicking the - (minus) button. Make sure you read the messages that Disk Utility presents you. You only want to remove the secondary partition, you do not want to affect the primary. If you get any message other than something like 'this will only remove the secondary partition and leave the primary unaffected', stop and re-group. Otherwise, go ahead and perform the removal. (You did backup, yes?)
Next, resize your primary partition to reabsorb that extra space. Edit the Size field by entering 9999 GB (or whatever). When you press return, Disk Utility will automatically change that to match the actual available space. Click Apply.
It can take several minutes for Disk Utility to verify and apply the changes. But it is able to make the changes (as it did with the original partition) in-place. You will not need to reboot afterwards, although you may want to just for sanity's sake.
Good luck and happy developing!