What operating systeme (iOS) version are you currently using on the iPad? You can find out by going to your Settings app, under General - About, then scroll down until you see version.
Generally speaking, to upgrade an iPad to the most current iOS, plug it into the most current version of iTunes (which is version 10.6 as of this writing), and select to restore. iTunes will handle the rest, you just have to follow the prompts.
One caution, however: Make sure you plug the iPad into the iTunes that you normally sync with, and do a backup of your iPad beforehand. Then, you won't lose your apps and settings because, once iTunes has updated your iPad, you can select to â€restore from backup," and option given by iTunes.
Once you are done, your iPad will be just like before, with all your apps and settings. And, it'll be on the lates version.
Hope this helps. Good luck and let us know how you get on.
Marilyn