For best BT experience, do the following:
1. Open TCP ports 6881 to 6889 on your PC or router.
To disable WinXP SP2 firewall, go to Security Center and select Off. However, u can set the firewall to allow certain ports such as above.
2. Cap your outgoing bandwidth to 3kB/sec or 6kB/sec, this will prevent BT client from hogging all your available bandwidth.
I capped mine at 3kB/sec and can download up to max 40kB/sec *using standard 384k Streamyx at home. It may take a little longer to download but my home PC is online 24x7.