reconcile 2 data sets with multiple variables

I have 2 sets of data. What's the best way to reconcile one against the other?

I've got 3 columns in each data set: dept, acct, and amount. I need to get the total amount per dept and account combination in data set #1 reconciled against the same thing from data set #2.

I don't know if a vlookup can work or pivot tables or some function I'm not already familiar with.... Help! Anyone have any suggestions on how to attack this?

What I'm trying to get around is creating 2 pivot tables from 2 data sets and manually comparing them line for line. The data would be grouped nicely but I'd still have 3500 lines to compare. I'm trying to figure out a way to automatically compare the 2 sheets and only review nonmatching amounts.

Any other thoughts?