There are only 2 freeware programs that I have found which have
provisions for annotations of lines, arrows and text boxes.
Both programs combine the ability with screen capture. The
first one I found is the previously mentioned 20/20. The
downside of it is that it has a forced add that appears a few
days after you install the program.
The other program is Screenshot Captor. The down side of it is
if you don't want to donate, you have to get some code from the
site to eliminate a nag for 6 months and then you have to go
back and get more code to operate another 6 months. Finally
after a year you can get some code to eliminate the nag
permanently. In spite of the inconvienence, I think it is worth
it and consider it better than 20/20. The screen shot functions
work good also.
http://www.donationcoder.com/Software/Mouser/screenshotcaptor/in d
ex.html