You haven't given any indication of your current training or fitness level and your profile is empty so no idea where you are starting from.
Have a look at this:-
http://www.209events.com/file/250.pdf
A plan for every level of ability and commitment.
I hope it helps, please don't just steam into the sub 38 mins plan with no previous training. As this assumes a certain level of fitness.
The get you round and sub 60 plans obviously more suited to a beginner.
The spiel at the top is also worth a read.