PRTG Freeware Edition
SNMP monitoring application:
ClickyThis application can monitor your SNMP enabled router and gather stats. It can display them in a pretty graphical format and has a built in web-server for remote access to the information.
Basically, monitor your home-server from anywhere for free!
The free version is limited to 3 sensors. I don't know about you, but I've only got one router...