I'm assuming that you want wireless internet (broadband).It depends on what connection your laptop has available. I have used:
Linksys Wireless Router + 4 Port Switch
http://www.expansys.com/product.asp?code=BEFW11S4
�41
and
PCMCIA Wireless Adapter
http://www.expansys.com/product.asp?code=WPC11
�24
This works great for me. I'm sure you can get the same devices cheaper elsewhere though.