What are some good exersizes to build up finger strength for moving on the fret board?

Chords are the easiest thing for me. But doing intricate melodies or just little pieces in a song that don't require chords are, like, h e l l for me. I think it's because I've been practicing chords for so long and haven't really dedicated much time to learning melodies and things like that. So, what I'm asking for is some techniques you know of that can make it a little easier. I know I've got to practice often, and my hands might not be as, um, nimble as they used to be because I do lots of barre-chords on a wide necked guitar (it's a Washburn classic). Any ideas?