You could try this, its what I use for FTP and other stuff, and have used it to host q3 games too
http://www.deerfield.com)
Look for, download and install DNS2GO. It will assign an actual name to your current IP address, whatever that IP is. And its free for non-commercial use :)
So for instance you could register zephyr77.d2g.com and all peeps would have to do is connect to that and the port# regardless of your IP.
Theres other such programs out there, but I like this one for the extras you get with the main program.
HTH