The best is SnagIt. It does everything. It is $50 or so, though. I saw a couple of freewares, but don't know if they are any good:

Farstone Capture

Screengrab (for Firefox)

flickr and WEBIMAGER

Window Clippings 1.5 - Kenny Kerr

__________________
Fredrick T. Greco
Senior Pastor, Christ Church PCA (Katy, TX)
Christ Church Blog

"The heart is the main thing in true religion...It is the hinge and turning-point in the condition of man's soul. If the heart is alive to God and quickened by the Spirit, the man is a living Christian. If the heart is dead and has not the Spirit, the man is dead before God." (J.C. Ryle)