Airport networking help

[Hal]

I have a question that involves using my Cube, so I thought I'd pose it 
to the group. I have cable modem service and have the cable modem 
connected to an Airport Base Station (graphite) that serves part of my 
house pretty well. I don't get coverage from the base in some parts of 
the house and want to extend the network.

Has anyone figured out how to bridge base stations, or use multiple 
base stations to act as repeaters? I haven't been able to find any good 
resources on this on the web. I'm currently using a G4 Cube, a Pismo, a 
400mHz iMac and  TiBook off the base station. The TiBook seems the most 
restricted in terms of range, but even the Pismo drops the signal in 
parts of the house or outside on the deck.

Any help is appreciated.

thanks,
-Hal