I found this solution elsewhere..
"I think it's been established that iPad sorts its photos by time stamp, earliest time/date first. The problem is where does it get the embedded date data from? And is it even embedded in every photo file? And how do you change the time stamp?
I'll cut to the chase and offer the solution.
First, sort the photo files in a folder on your PC hardrive in the order you want them to appear in the iPad album.
Next, open the first file you want to appear in the album with a photo edit program. I used Picassa, but I assume that Photoshop Elements or similar programs would do the same. After opening the file, then simply click "save as" and rename the file (not even sure if the renaming is necessary). Direct the "saved-as" files to a new folder.
Next open the second photo you want to appear in your iPad album and do same. Continue with all the photos, automatically resetting the date/time stamp each time you save it.
Now open Itunes and sync to the new folder you created with the re-dated photo files.
Voila, you now have a photo album on the Ipad exactly as you want. "
Tim