Crack my wireless WEP Key

would like to test my wireless security by cracking my wep/wpa keys. I've been having problems using Backtrack packet injection. What I need is for someone to guide me through the process or build me an ubuntu iso with everything i need already preinstalled and to guide me through the cracking process for my network. This is the hardware I have: Gateway Laptop windows XP. This should be easy project for someone who knows what they are doing.