TSW is cross-server, so pick whichever one you like.
To join the ingame /v/ chat type /chat join vidya

To auto-join your preferred chat channels: Create a folder named "scripts" in your TSW folder, and create two text files named "auto_login" and "auto_teleport" (WITHOUT a file extension) and enter the following:

delay 5000
/chat join vidya
/chat join sanctuary
/chat join noobmares
/chat join event

Sanctuary is a generally helpful chat channel. Noobmares is for later on, when you start doing Nightmare dungeons (althugh you can sometimes ask for Elite groups,too). Event is for, duh, events.