I ran across this package today: http://www.cleardata.biz/cleartrace/default.aspx
I'm playing with it now. It basically reads a SQL Server Trace file and shows you the longer running processes so you can do more performance tuning. It's a freebie, and also in beta. I don't know if they will charge for it in the future.
You can do the same thing yourself with Transact-SQL, and of course there are memory limitations, but it seems like an interesting toy to play with.
As always, load this kind of thing in a test environment (a VPC is ideal for that), your mileage may vary, don't run with scissors, etc.