If you are still on Froyo & do not want to update to gingerbread for some reason but would like to install Clockworkmod Recovery (CWM), then no need to worry. Here is a tutorial to do exactly that.
- Run Odin.
- Select the Cooper.ops file in OPS field.
- Select ‘recovery_gamma_froyo.tar‘ in PDA field.
- Put your Ace in Download mode (by holding Volume down+Home+Power key during boot)
- Connect your phone via USB. If Odin detects your phone, a yellow box will appear with port number.
- Click on Start.
- Wait until the yellow box goes blue with message “PASS“
Unplug USB & restart the phone. And you’re done.