As it says in the heading really. Whilst there are big gaps there is a huge amount of information on http://reggaelicious.pbwiki.com/
including tons of stuff about sound systems... check the list for example http://reggaelicious.pbwiki.com/List+Of+Sound+Systems

ooh I like that- very useful. thanks alot for the tip

there's actually a suprising amount of good stuff on Wikipedia about reggae as well (if you search for artists anyway)
http://en.wikipedia.org/wiki/Main_Page