To use a Bluetooth keyboard and a mouse at the same time, check out BTC Mouse & Trackpad.

It provides a better user experience by integrating with the iOS Bluetooth Stack instead of replacing it. New features incl. automatic reconnect, zoom/pinch and swipe simulations

Bluetooth Mouse Support

Use a standard Bluetooth Mouse with your iPhone/iPod touch.

Does not work with Apple Mighty Mouse

Known issue: Dragging the "Connected" view, causes Mouse to hang on iOS 4 => don't drag it

Uses the MouseSupport extension to actually show a mouse pointer. Does not work on first generation iPod touch. Works great with BTstack Keyboard.