One of the easiest ways to learn is by simply going to guitar tab archives online and printing off tab for songs that you like, and then play along with the CD.

There are a lot of simple tabs out there that contain chords and lyrics with exactly on what fret and string to stick your fingers.

Try guitartab universe or something like it.

As to the knackered fingers bit, just keep practising as your fingers will gradually get use to the ill treatment.