802.11b Security?

I went out and bought a Netgear MR814 4-Port Cable/DSL Wireless Router(802.11b)

Using a Linksys Wireless-B USB Network Adapter also 802.11b of course.

I have never used Wireless before, it just took me 2 hours to get the wireless network to work on my roomates PC. Everything works, but I do not want to have others connecting to my network and using MY(err OUR) Bandwidth

Or hacking of course.

Other then changing the password to get into the router, what can I do to ensure more safety?