It notes to use WPA-PSK, enable SSID, latest firmware and a few other points. Your post did list the hardware (good) but omitted settings, distances involved, firmware versions, etc.
I just purchased a new computer recently, and proceeded in connecting it to my home network. My wireless router is a Dlink DI-524, and the wireless dongle is an external Dlink DWL-G122.
On my computer that is connected wirelessly, Internet hardly works at all. Whenever i try to load a page in a web browser, it manages to get through "connecting to www.google.com" but stops completely at "waiting for www.google.com" Also, I ran MSN troubleshooter and it says theres an error with my "key ports"
About once every 30 mins or so, I can use the net like normal, but within 5 mins it reverts back to hanging on "www.google.com" Its not a browser issue, as every application I use does something similar, such as games hanging on "Logging into server" as opposed to hanging on "connecting"
Also, all my wireless computer is running XP SP1, and is updated with the latest wireless drivers and my router is updated with the latest firmware. And my internet is 256kbps adsl. Modem is a Dlink DSL-302G
Hope you can help, and i apologize for my lack of proper terminology/spelling.