Used Bitinstant today.  Got my money deposited in like 5 minutes.  Did two different transactions.  Very satisfied.

I suggest going to your destination site though.  I went to mtgox and to blockchain.info and created accounts and followed their directions.

I also tried just going to Bitinstant and doing it directly, but somehow it didn't load right and it was confusing and a waste of time. 

A very important thing is to check your email account for all the final directions.

Overall A+.  There are tons of locations in town where I could use cash to deposit into Bitinstant.  Just get ready to fill out the paperwork.  Takes a few minutes.