Trellis Desk
Trellis Desk is a user-friendly, clean, but powerful help desk system. It has many features, including custom department / profile fields, rich text editor support, ACP permissions, department permissions, escalation control, RSS feeds, statistics, advanced logging, email piping, guest ticketing, canned replies, custom pages, API / module support and much more. Knowledge Base categories and departments make it easier to find content. Email piping allows support / ticket management all through email. You can also use the skin and language manager, to customize the look & feel of Trellis Desk to fit your website.