Watch the Reading Music online guitar lesson by Bruce Arnold from Jazz Guitar for Beginners
The PDF of a common chord chart will help you understand the common ways that music is presented. Sometimes there are the actual notes present.
This usually happens when there are notes that are not specific to a common chord. The rhythmic notation looks slightly different but Im sure you will quickly pick up that its very similar to just reading rhythms.
The real secret of reading on the guitar is just to do it every day for a few minutes and eventually your ability will improve.
I've recommended books to read through, so make time each day for a little reading and it will pay off big time down the road.