If you do a little research you can probably e-mail via the command line. Once you figure that out, set up a cron job to e-mail out periodically. Cron jobs aren't hard to setup so if you do a little research on google (based on your distribution) it shouldn't be hard to setup.
You should be able to write a small awk / sed / grep script that can pull out the IP Address of the interface you want. This small script can be enclosed in `` (tic marks) so it can be included in the text of your e-mail.
This would pull out the IP address for interface eth0
`$IFC $EXTIF|$G addr:|$SED 's/.*addr:\([^ ]*\) .*/\1/'`
** Code from -- IPTables for Newbies
I hope this helps,