As well as setting up the Airport Express and AirTunes, I've been attempting to attach an old USB Lexmark Z52 printer to the Airport Express unit. This printer works when plugged directly into my Mac. However when I try to print wirelessly to it the print job spools to 100% and then stops itself. Opening the print queue shows my print job has stopped itself with a message which reads "Printer: Jobs Stopped".
Despite some extensive searching, I couldn't find the solution. I tried reinstalling the Lexmark drivers from Panther disc 2, a tedious job, but to no avail. This discussion describes my exact symptoms, but the given solution didn't improve my situation at all. After spending a couple of frustrating hours reading the Apple discussion forums, I stumbled across this page which lists Airport Express compatible printers, and the Z52 is not listed as being compatible. However I couldn't be sure since the Lexmark page on Airport compatibility has been down for the last several hours. To be honest, it's a relief to find out. At least I know how to fix the problem now! (The Z52 was a hand-me-down, and virtually not worth using in any case due to the extortionate cost of ink cartridges).
Edit: while typing up this entry, I attempted to print this page in order to double-check the exact wording of the print queue error. The printer name had a small exclamation mark next to it so I clicked 'Printers' and 'Rendezvous' and choose the Lexmark Z52 again. This created a new printer, and lo and behold, the damn page printed out! This is almost too annoying for words - I must have deleted and recreated the printer a dozen times using this exact same method without result, and now the damn thing decides to start working for no apparent reason. It's good to know it works, but I will still be replacing the printer shortly - it's too big and the ink costs almost 20 times as much as Canon cartridges.