Actually it's trivial to hack into a wireless network the way they are now. If you visit bawug.org, you'll find links that take you to linux programs that can crack a wireless network in about 30 minutes or less or so they say. That's assuming there is any protection on the network as it is, there often isn't. Be wary of war-driving.
That said, you can make the wireless network secure for your system but that's a non-trivial task. Basically put the WAP outside your internal wired LAN (you probably need to buy at least one more switch or router to do this). Run NAT on the WAP to share your IP address with your wired network, run your wired network with any security you feel like using -- search openacs or aD for firewall and sonicwall, and then install some VPN somewhere on your LAN.
That VPN can probably be a Linux or Windows app. Install a VPN client on your wireless devices. So now to access your LAN from your wireless unit, you VPN in through your firewall, the VPN software may/should let you see the rest of your LAN the network.
At this point, realizing that my $200 WAP + $50 switch was only going to yield me maybe 4MBps, while the $50 switch and a big $25 cat 5 cable was going to crank up my speeds to 100MBps, I returned the WAP.
Other note: one benefit of running your own servers that I haven't seen mentioned above are the benefits of running your own mail servers. Qmail in particular let's you create a gazillion unique email addresses. So each time you find someone wanting your email address you can give them a unique email address that gets back to you. Very useful in tracking down the source of SPAM, and in then allowing you to create precise filters that get rid of the SPAM and nothing else.
