Sci-fi/Real space Links
Starship Modeler

Great site for sci-fi, real space, fantasy & anime modelling. Loads of reference pics for all the popular TV & movie spaceships, robots and hardware so you have no excuse not to get the colour of Luke Skywalker's socks correct....
VooDoo FX

Excellent sci-fi model lighting kits by Randy Neubert. Custom tailored to suit available injection moulded & resin kits. Service is top notch and Randy is a great guy to deal with.
The Apollo Saturn Reference Page
A goldmine of information on the Apollo Saturn program (thus the name). Tons of photos & information plus a modelling section.
Space in Miniature
Good informative site with lots of pics on real space hardware. Also a series of very good reference books available for the space shuttle, lunar module, soviet spacecraft, etc.
David Sisson Models
David is a bit of a Gerry Anderson nut and his large scale scratchbuilt models from Space 1999, Thunderbirds, Captain Scarlet et al are truly works of art. David also owns one of the original Eagle studio models and his article on restoring it is well worth a read.