Basically you just need a Wireless router...then you need a wireless card for each computer. Unless maybe one computer will be near the router, then you can just run a cat5 cable to that one.
The router takes the signal from the broadband modem and then splits it out to each computer.
Here is an example of a wireless router....these home type routers are very popular nowadays and easy to setup....they almost all have 4 regular "wired" ports and if they are wireless they have one or two antennas.
Router
http://www.dlink.com/products/?model=DI-614%2b
Then for your laptop you will need one of these wireless adapters, for example
http://www.dlink.com/products/?pid=9
For your desktop you could either use one of these PCI type adapters
http://www.dlink.com/products/?pid=24
or one of these usb type, sometimes the usb type are cooler because you can move them around to get the antenna in the best spot for reception
http://www.dlink.com/products/?pid=25
Make sure that all your parts use the same "standard".
802.11b is the most widespread standard...it is rated for 22Mbs
802.11g is the newest standard, it is faster and also it is backwardly compatible with 802.11b.
802.11a was a faster alternative to 802.11b but it didnt really catch on too well...so I wouldnt bother with it.
Good luck, JP