Some examples include:
Not Ready to Make Nice - Dixie Chicks
What Have We Become - DC Talk
Dear Mr. President - P!nk
War on Drugs - Barenaked Ladies
almost every song by Chumbawamba
The thing that is odd about all of this, is that I completely ignore politics in any other realm. Ie. I don't watch the news or read newspapers, but I totally dig this stuff when it is mixed with music.
Just one new thing I have learned about myself. :)