HelpScout - Help Scout is a simple, straightforward way to provide excellent support
Issuetrak - Issue tracking software for help desk and customer service
HelpNinja - Simple & Affordable help desk
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.
SupportYourApp - Connecting talented people with the blooming IT industry to help them grow faster by outsourcing support.
Kapdesk - Kapdesk offers support teams with a helpdesk software to streamline support tasks.