Bittering hops?
 

Do bittering hops add any flavor/aroma to the finished beer, or are they there just for their AA's?

Just for the AAs. The hops for flavor and aroma are added later in the boil usually at times from 30 minutes to 5 minutes left in the boil. Sometimes hops are even added at flame out. Some styles benefit from dry hopping which involved no boiling at all. The hops are placed either in the primary or secondary fermenter to add aroma.

Thanks. Need to stock up on hops again and didnt want to do something that would change the overall flavor of the beer.

Actually, it has some impact on the flavour of the beer, you have to be careful doing substitutions, even for bittering hops; not as much as with the aroma hops, but still...

Bittering hops will leave some flavor and aroma. It's most noticeable in light styles that have minimal hopping, especially when you use, say and ounce or so of something like Hallertau or Tettnang compared to only a half ounce of Magnum. Both will give you about the same bitterness units, but the one ounce of lower alpha hops will give you more hop flavor and aroma.

Not to complicate the issue further, but...I'm gonna. :D

Some varieties of hops are so strong that no amount of boiling will drive off flavor and aroma compounds. Read up on all of the varieties before you go plunking down any money; read a variety of sources, too, to be sure.

Cheers,

Bob