Losing wireless connection on mac but not on pc

I have an iBook G4, along with a PC laptop. Recently I've had to reconfigure the iBook network configurations almost every time after the computer has gone to sleep. It's not difficult to do, but it is annoying. The only thing that I can think is that I recently upgraded to Leopard (10.5.8). Does anyone know whether there is a glitch with Leopard that's causing me to lose my network connection?