Just start with basic pentatonic scale stuff. Keep it simple and don't stop playing chords. If you're leader wants lead, YOU CAN do that. Find an open spot in the song and play a couple of notes from a scale in the proper key. Remember you're not playing rock n' roll. It's P&W. Remember also that there is a difference between playing lead and playing solos. Here is a link to get you started
http://www.guitar-dreams.com/guitarl...ssonid-13.html
You can also do a google search for "pentatonic guitar scale" or something like that, and find all sorts of good stuff. Start there and build your repertoire on that. It's not the only way to play lead, but it is the simplest and most common.
And don't worry if you don't sound like what's on the CD or like your friend. (Also it sounds like he would be a great resource. Maybe give him a call and see what he says.)