database design question

I have this site with Open Source Software for Windows:

http://users.pandora.be/vandewoestyne/html/open_source_windows.html

I would like to convert it to a MySQL+PHP thing. Right now, I'm thinking about the design of the database. The ER-diagram I currently have is in .dia format available at
http://azw.dyns.be:9090/oss_windows/oss_windowsdb.dia

I just would like to get some comments on this diagram. Am i forgetting stuff? Any better suggestions?

Especially comments on how to organize the fact that a project can be in a subcategory that is part of a main category.

Thanks,
Bart

PS: is this the correct place to ask ER-design questions like this? If not, what other newsgroup is more appropriate?

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Bart Vandewoestyne		      Bart.Vandewoestyne_at_pandora.be
Hugo Verrieststraat 48			       GSM: +32 (0)478 397 697
B-8550 Zwevegem			 http://users.pandora.be/vandewoestyne
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"Any fool can know, the point is to understand." - Albert Einstein