Fair use guide
Given all the stuff flying across the Internet about the AP and "fair use," I'd recommend you look at Gabriel Malor's explanation of the ins and outs of the concept.
As he says, he's not a lawyer, but it's probably the best plain-spoken explanation I've seen, especially in clearing up a lot of misconceptions about what fair use of a photo or other visuals is.
- The Electronic Frontier Foundation's FAQ.
- A highly intelligent discussion of the AP dustup and the wider ramifications from Christopher Sprigman at the University of Virginia.