Definitely look up "Low Rider" by WAr (theme song for George Lopez Show)... it's pretty basic, but it will help you understand why hammer on's are important (hammer on's are noted with a "/", so you would hammer on the 5th fret from the 3rd in this song). Most of the tabs on the net are wrong so here is the correct line:
G--|---------------------------|
D--|--------------3----3/5-3/5-|
A--|-----1--3--5-----5---------|
E--|1-3------------------------|
sometimes, it goes like this (change at the end of the bar):
G--|-----------------------3/5-|
D--|--------------3----3/5-----|
A--|-----1--3--5-----5---------|
E--|1-3------------------------|
Enjoy!
Oh, and "Beat It" by Michael Jackson is a good one, too.
EDIT: Also, try doing the "Low Rider" line withOUT the hammer on's and notice the difference. Takes out the funk lol