ClockworkMod (by Koush) is an alternate recovery for Android phones. It allows you to make nandroid backups of your Exhibit, as well as offering utilities to troubleshoot problems.
Download standalone ClockworkMod 18.104.22.168 HERE
It is also available as part of jocala's custom kernel HERE
You'll also find it in most Exhibit II custom ROMs.
Both ClockworkMod and the custom kernel/ClockworkMod combo can be flashed from Samsung's stock recovery. If you are flashing from stock, be sure to copy the zip file to your internal sdcard. Samsung's recovery will not detect the external card.
Both archives above contain a file called "recovery.img." This recovery.img file is actually a combined kernel and root file system with the program /sbin/recovery being the actual ClockworkMod program. If you like, you can also extract the recovery.img file from either of the two zip archives above and flash via the command line.
(command line can be a rooted adb shell or a rooted terminal on your device)
dd if=./recovery.img of=/dev/block/mmcblk0p13
From a rooted terminal, "reboot recovery" to start ClockworkMod. From your computer the command "adb reboot recovery" works too.
To start Recovery (ClockworkMod) from power-off.: Press & hold Vol-Up, then press & hold Power. Shortly after the plain white Samsung logo appears, release both buttons. ClockworkMod should start after the color Samsung/T-Mobile Exhibit II logo.
CWM Keys: Home key = enter Back key = back VolUp/Dwn = highlight choice