EttercapNG 0.7.0_pre1 Released
Fairly recently updated, EttercapNG is out. You will need an updated libpcap (version 0.8.3 should be fine -- has to be greater than 0.8.1) and libnet greater than 1.1.2. Don't forget OpenSSL if you want HTTPS and SSH1 support.
Just as a side FYI, when installing libpcap, I had to copy a version from /usr/local/lib to /usr/lib so if it is having errors trying to find libpcap do a whereis libpcap and then do a strings on each libpcap.a file location.
Addendum
Ettercap ended up in /usr/local/bin/ rather than /usr/local/sbin. Either copying it over of creating a link should do the trick. The Interface has changed. You now can choose between ettercap -T for a text/CLI interface, ettercap -C for a nCurses interface or (NEW) ettercap -G for a GTK interface. Definately need a read of the man pages for the vast changes they've done with this tool.
Happy Sniffing! :D
Edited to fix the -T