If I buy a wireless router modem, can I plug in the desktop PC and use a laptop PC and a desktop MAC wirelessly or are the two kinds of machines incompatible?

And assuming they will work, does the desktop PC have to be on for either of the other machines to use printers connected to it?

 

Both machines will work fine through a wireless router...

If the printers aren't network-printers, plugged directly into the router, then I'm pretty sure the PC will need to be plugged in (although I've never really messed around with printing over a network like that, so may be wrong on that part).

 

I have a printer connected directly to a PC, which is connected to my router, to which another two PC's are connected - and spent the best part of a year trying to get the other two PC's to print to the printer with no success - so I gave up Fitted a cuple of bluetooth dongles to the machines and now when something needs printing, I just bluetooth it from one machine, to the machine connected to the printer and then go to that machine and print

 

I run a wireless Print server which is detected on the network as a device with a MAC address (Media Access Control Address like a network card)
All that you have to do is set the computers up to print to a IP address (the static IP address of the print server) and it all works..
Printing over network computers never works well as the computer that the printer is connected to must be on as well as the printer to work..
For the price of 30-40 quid a print server is a must have for me personally

Canon actually now sell a range of wireless printers which produce fatastic quality prints