Issuetrak - Issue tracking software for help desk and customer service
HelpScout - Help Scout is a simple, straightforward way to provide excellent support
Deskun - Deskun is a Help Desk system inside Gmail. It enables you to support customers directly from your mailbox, manage projects, and use free features for Gmail.
HelpNinja - Simple & Affordable help desk
Kapdesk - Kapdesk offers support teams with a helpdesk software to streamline support tasks.
SupportYourApp - Connecting talented people with the blooming IT industry to help them grow faster by outsourcing support.