Shakespeer has always been my favourite. There are a few things to do...
1) Open preferences, enter a user name.
2) Go to the share tab, add in some files. You need the minimum amount or you can't connect to the mac DC++.
3) Close prefs, click Connect to Hub. Enter machub.dyndns.org in the Address area. Make sure your nickname is in there too.
4) Click connect, and go crazy!
Ps in the advanced tab of the prefs, make sure "Reconnect to last connected hubs on startup" is checked, it'll make things lots easier.