Project management software?

Anyone have any recommendations for (preferably free or cheap) project management software, the kind that helps you figure out scheduling with interdependency (i.e., he can’t finish X 'til five business days after I finish Y)? I gots me a new contract job.

Edit: crap…forgot the name of it…

Found this on Wiki: Comparison of project management software - Wikipedia (shoot - it abbreviated the link - it reads “Comparison of Project Management Software”)

I don’t have first-hand experience with these apps…

I played around with a couple of free ones last quarter for the project management module of my ICT degree. Since this was just for an intro class I wasn’t getting really deep into any of the programs, but the one I found easiest to use was open workbench:

http://www.openworkbench.org/

Free and easy-to-use program for making Gantt Charts.