ahh, one of my favorite topics. I use this all the time (only in my lab, of course). but the "network" statement does two things:
1. If the interface IP falls within the IP range, than participate in the eigrp neighbor process (send out hello's and updates, etc..). this can be stopped by using the passive-interface command.
2. The second thing it does is: If the interface IP fails within the IP range, than advertise my subnet into EIGRP.
so it I have three interfaces:
s0/1 - 192.168.1.1 255.255.255.252
s0/2 - 192.168.2.1 255.255.255.252
s0/3 - 10.1.1.1 255.255.255.0
and I have a network statement of "network 192.168.0.0". that would then match the first two interfaces and they both would 1. participate in the neighbor process and 2. advertise the subnet.
The "network 0.0.0.0" would match all interfaces.