Use a hardware keyboard/mouse to send keystrokes to an Android phone

• BlueKeyboard by Elbrain
• BlueInput by TekSoft
• Bluetooth Keyboard Easyconnect by Mike van der Sluis
• Null Keyboard

Use an Android phone to send keystrokes to a computer

• v.:mote by FrankieSoft
• Phone Mouse by Seth Mayberry
• BlueputDroid by Berserker
• GPad by mobisters
• mousless by Jerry Wu

other bluetooth pairing apps (that require NO special software to be installed on the PC)

• network
  • tetherBlu
• NMEA (GPS) over serial port
  • Network/Bluetooth GPS
  • Bluetooth GPS Output
• printer
  • Bluetooth Smart Printing
• file transfer
  • Bluetooth File Transfer