I've written about using Wireshark to look at signalling captured from an E1/T1 before. As of a few days ago, it's possible to do live captures on Windows, like this:

 start save_to_pcap 172.16.1.10 1A 2A 16 \\.\pipe\ss7.1
 wireshark -k -i \\.\pipe\ss7.1

The new version of 'save_to_pcap' program is part of the C examples, the .zip file contains both source (compiles on Unix and Windows) and .exe files.

It's always been possible to do live captures on Unix, you just pipe stdout:

./save_to_pcap gth21 1A 2A 16 - | wireshark -k -i -