I happen to have that link handy.
Setting up Google Sync with your iOS device : Mail, Calendar, & Contacts - Google Mobile Help
If you don't want to sync the desktop programs to GMail, you can export your contacts as .csv or vCard files and then import them to GMail.
While the Contacts app on the iPad does not look exactly like a rolodex, I think you'll find it easy enough to use. There is an alphabet tab to the left of the contact list that you can tap to jump to different areas of the list. Not much different than a rolodex.