Well if you want an easy scale to start out with for playing lead, learn the minor pentatonic scale. Learn it in E for starters so you will get the hang of not staying in 1 posion the whole time, because E pentatonic is so easy to move to the open positon, or 5th, or pretty much anywhere once you learn. Just search on google for pentatonic scale and some site will have a daigram of it. It's very simple and if you want to play it in the key of E, start out with your index finger on the 12th fret. As far as playing fast goes, practice with a metronome (spelling?) and build up your speed slowly. Make sure you have good picking techniques at slow speeds before going super fast. If you can't do something slow, you sure can't do it fast.