We used to be on Dalnet, but they are too open, denial of service attacks has made the network almost unusable. Undernet may not have as many toys as Dalnet but you aren't going to have continuing problems connecting to a server.
If you don't have and don't want to install an IRC client, there is a web interface at
www.undernet.org, just join any listed channel then type /join #pcmech. Requires Java.