First, I would check that your Wi-Fi network is set up, run winipcfg on each PC and select the wireless adapter to get their IP addresses. Then I would try and 'ping' the other PC's IP address from each PC to make sure you have a working connection.
If this works well, then an option for transferring files would be FTP; XP professional comes with a built in FTP server, there are also plenty of free/cheap and simple ones to download. Internet explorer can act as an FTP client.
Sorry, I was meant to say i can't get up and running any networks.
I am actually connecting them through 2 wifi card by adhoc. Internet sharing works, once I can't use the microsoft file sharing thing. I have enabled filesharing and set some folders to share, also they workgroup names are the same. I can also use aprogram called tightVNC to control one PC remotely, using an softAP on one fo the wifi cards. I only wanted to set the network up to transfer files wirelessly, since tightVNC can control one pc from ther other with out setting up a wireless network through microsoft windows, i thought there might be programs out there that can actually transfer files through wifi, like you do with FTP's or messenger programs ( e.g. yahoo, msn). Doing a google search I've found nothing. Also, how do I use ftp to transfer the files? if i use I.E. is the webaddress just the ip address of the other computer? and do i need to set up filesharing for that to work anyway, which it isn't.
The bottom line is using ADhoc on XP is problematic from the posts I have read in this NG. You can xfer files wireless with the XP O/S using F & P sharing and a wireless router as a gateway device with no problem. You can use FTP software wireless too. You can do anything you want between to machine wireless just like you can do wire to wire but apparently ADhoc wireless to wireless is problematic with XP.
You should look into to getting wire/wireless NAT router and use it has the gateway device for the LAN and WAN and use Infrastructure mode on the cards.