Well, you might be having ping issues when people play you simply because your bandwith isn't large enough. 56k really never connects at 56k, the highest it connects at is 48k, which you probably aren't even getting. Also, we've no idea what ISP you use, depending on the ISP you could have even more ping issues.
Personally, if I were you, I'd give up on trying to host a game when you have a 56k connection. Jjax, if your friend has cable, then he should serve instead.
I wish you both good luck serving...but I'd wait till ya get a faster connection!
-I_AM