Hi there!!
In my case MS Powerpoint is quite sufficient. Does the jom plain and simple.
3-4 times I experienced some difficulties and for that reason I used Smartdraw. There is a new version for 2010. Is also quite simple.
It is not freeware, but probably you can find somewhere (not including how or where, of course I know but I am now sure if we allowed to share links of that kind)
However, you should try MS Powerpoint, is my advice.
All the best