voltage question

please can some one let me know what i need to reduce the 10v output from my microwave proximity sensor down to 5 volts so I can wire it into the arduino.

urgently need to know what i need and where to get it, i'm in the UK.

thanks in advance :-/

Please don't cross post it really pisses people off.

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1281513934

i'm in the UK.

I am disappointed by a cross posting person living in the UK.