over the past couple of days i have done some contact managing on my iphone...my question is when i hook it back up to my computer and sync up again will it revert the iphone contacts back to what the computer has??
No, it won't. It actually should prompt you if you change more than 5% of your contacts. If you make changes on your computer then sync the iPhone it won't prompt you.
I think the sync from iPhone overwrites what is on the computer. It doesn't look like it is additive. But I could be wrong.