IP Security Cameras

New kind o' network job landed in my hands;
I'm helping a client put an IP camera in each of his stores;
3 don't work & 3 do (1 just needed to reset the camera & port after a
power failure).

The remaining stores have ATT/ma bell's netopia routers (setting into
bridge mode),
which drop over to linksys routers; non-wireless 4 ports w/ a wan i/o.
The prior tech hadn't requested a block of static IP's, which I just
did Friday, after a LONG run-around to confirm that I was an
authorized person to modify the account....
_____________
This is where I need help;
Now I need to poke a hole thru the linksys,
to allow the camera(s) to send out to the net, using a new static IP.

Any hints, warnings, or provisos would be greatly appreciated!
Thanks kindly!
Amanda