I just got an Aspire 3502 WLCI (maybe the same one you have, if not it's very similar).
You will want to install 'ndiswrapper' if you don't have it already, and then look in the c:\windows\system32\drivers directory for the .INF file with the driver information for the built-in WiFi (an Atheros AR5005G in my case).
I just found out there may be a native driver for the card, which would be much better than using ndiswrapper -- but my laptop *is* working w/ the ndiswrapper solution.
A bigger problem is that suspend doesn't work. I also have an Acer Travelmate 2303 and suspend doesn't work on THAT, either. My previous laptops were Toshibas, and they always worked ok