I found there are many free software which could be applied in medical education. For Examples :
1. Blog or web blog can be used for learning diarry or electronic log books. Medical students may write theirs experience in log books. The advantages the log book is improve their reflection about their learning experiences. I used free software such wordpress with server2go to build electronic log books which run in USB flash, CD or computers. The log books contain learning experiences, reflections and planning about improvement for the future (this term mix with portfolio)
2. Wiki can be used to build collaboration learning. Now , there is http://www.wetpaint.com/.
The wetpaint.com provide wiki host to build collaboration and sharing knowledge. Medical students can join and participate to build knowledge. I think there is contructivist learning theory there.
4. Electronic book compiler. This software usefull to produce electronic book. There are many type such CHM compiler, PDF creator or EXE builder. E bookMaestro compiler and natata ebook compiler may usefull to build Ebook.