I don't know if you have seen the blog by the Librarian in Black, but it is something that I look at regularly. It has some great free resources and focused on libraries and librarians. This is a good for all information professionals, plus she has some great commentary and you can't beat free!
The recent post, 13 Ways (and 147 Tools) to Help Your Library Save Money on Technology, is a good list that is focused on technology. I had never heard of Drupal, a content management system, but I now have it on my list of things to investigate. I LOVE NEW TOOLS!
Let us know if there is a free tool that you use on a regular basis by adding a comment below.