Are your contacts already synced with a service like MobileMe, Google, or Exchange. If they are import your contacts there instead. Much easier and you'll find more tools to do the job.
If not, then I recommend getting a free Google mail account and using it's contacts features.
What you will want to do, without getting into to many details.
Create your Google email account.
Go into contacts and add a few sample contacts. Be sure to add all the same fields you will want with the imported contacts.
Use the More Actions menu item to export all the contacts as a CSV file.
Import the CSV file into Excel.
Compair the two files. Copy and paste from your master file to the the Google Excel file to get all you info in it. When you have it ready export the new file as a CSV.
Go back to Google Contacts and use the Import CSV option. Carefully check to make sure all contacts are looking right.
Now, finally, on your iPad:
Go into Settings > Mail, Contacts, Calendars and add an account using this method:
http://www.google.com/support/mobile...&answer=138740
After it is added open the account and turn off Calendar or Mail syncing if you don't want them.
Go to the Address Book and check to see if it worked.
You can delete the Google account from the iPad if you want to after it is over. Just be careful not to tap the delete all data choice when doing so. Or leave the account active for easy one stop editing of the contact list later.
Cowardly Disclaimer:
This should work. I know people who have made it work with Android devices, Exchange, and when migrating from Black Berries. BUT, I've never done it myself, and there are multiple ways for it to go wrong.
On the other hand, none of your original files are at risk and it's all undoable. So all you really risk is wasting your time. If you can't find a better one stop method this may be your only choice.