Sorry for such a newbie question, but I wanted to get the pros advice, so this I came here. Please help me.

Some friends talked me into a team triathlon in a MONTH (yikes). I'm doing the 40k cycling leg, using my brother's Trek 2300. I'm a 6'3", 225 Lb male in fair shape. I'm not much of a cyclist. My goal for this event is to not humiliate myself doing this. I hope I'm not in over my head.

What suggestions do you have for a training plan?
Should I get a heart rate monitor?
What other advice can you give me?