Try before Buy :
http://slideme.org/application/advanced-touchpad

Description :

Advanced Touchpad turns your Android device into a wireless touchpad (mouse) and keyboard to control your PC.

Instructions :

1. Download the server from http://www.arcoid.net/downloads.php
2. Exctract and run "Advanced Touchpad Server.exe" on your PC.
3. On your device go to "Menu->Auto Discover" and choose one IP Address from the popup list.

Features :

• Supports Windows XP & Windows 7.
• Automatic detects computers (no need to manually configure IP address).
• Wireless mouse.
• Wireless keyboard.
• Simple and powerful user interface.
• Supports portrait and landscape modes.
• Auto enable WiFi (no need to activate WiFi before starting it).
• Vertical and horizontal scrollbars.
• Two-Finger scrolling (vertical and horizontal).
• Pinch To Zoom.
• Tap to click.
• Double tap to double click.
• Tap lock (when dragging).
• 3 mouse buttons.
• Sensitivity control.
• Support special characters.
• Auto run with Windows feature (in Windows 7 right click and run as administrator).
• Acceleration Threshold control.
• Haptic feedback.
• Improved sensitivity control.
• T9 is supported.
• Smiley keys are supported (not every keyboard has smiley keys).
• Special Keys (Ctrl, Alt, Arrows, F1, ...).
• Multimedia Keys (Play, Pause, Stop, ...).
• Explorer Keys (Home, Back, Refresh, ...).
• Auto "Tap Lock" Release.
• Swap left and right buttons.

Screenshots: