Yes, but it depends on how savvy you are about networking. You can run the wireless card in AP/master mode (your card has to support this) and use other machines to connect to it wirelessly. If the machine is also wired you can use it as a gateway.
Though really, it'd probably be easier to just get a wireless router.
Either way, you'd probably just want to run a fileserver on it, samba/smb, nfs, etc.
Try the HP MediaVault mv2000 or mv5000 series. I have a 300GB mv2010 series. It is plugged into my switch that goes to my router. You type its local IP address into your browser. For me, I type in 192.168.0.106, or I go to My Computer, and type into the address bar \\192.168.0.106\[folder name]. It is so simple. Turn it on and leave it. I highly suggest getting one if you want simplicity and reliability (I have had it over a year, and still works great). I hope this is what you're asking...
9My home server is just a bunch of spare parts I've thrown together into a random case. I put 3 NICs (ethernet devices) into it, giving me DHCP, DNS (Which is TONS better than using IP address all time -- especially when you have a lot of machines on the network like I do) , Web, and... well, that's it. Since that's really all my server does; I gave it 256MB of RAM, on a 40GB IDE drive. You never need anything fancy. Anything 500MHz+ these days can be made into a decent CLI server.
I have other servers that do other things as well, that handle different tasks (and have different specs)