That was one of the first things I said to do. If you named it update and didn't get a warning about changing the file extension you're good to go with it as update.
Cool stuff you should have... Depends entirely on your circumstances. SetCPU from the market for overclocking, Quadrant to benchmark your machine (meaningless but cool), Drocap2 to take screenshots, titanium backup to make backups of your apps... The list is long and fun. Play around and enjoy!