How do I consolidate all my BTC into a single address? I'd like to archive all my coins in a single address (specifically the address for a "brain wallet").

What is the most effective way to combine all the outstanding balances into a given address?
Once you have the address you'd like the coins to be in, just make one transaction for the total amount of your balance going to that address.  The inputs from all transactions leading into the sending wallet will be combined into a single output automatically.  Or are you asking how to create the brain wallet in the first place?