This site has some good tips for speeding up firefox:

http://www.911networks.com/book/print/8

The quick and simple stuff is as follows:

Open firefox and in the address type type:

about:config

This will display the preference name, the status, the type and the value.

If the configuration setting already exist: double click on it and then change the value.

If the configuration setting does NOT exist: right click on the web page, New, the depensing on the preference it's either a string, an integer [number] or a boolean [true/false]

network.http.pipelining true
network.http.pipelining.firstrequest true
network.http.pipelining.maxrequests 8
nglayout.initialpaint.delay 0