I've used TRAC for tracking bugs/issues for software development but it seems a bit complex for a typical desktop user. Is there anything better (open source) that would be simpler to use (than TRAC), aimed more at end users(not developers), and perhaps walk them through common scenarios?
Wikipedia has a Comparison of issue tracking systems
At my current work we use Redmine. I don't know if that counts as "simpler", but it works well for us.
Non Software: I At a previous place of work that we use to work at, we used OTRS (http://otrs.org/) It is for a non-development environment (doesn't have fixed in build, found in build etc..). We set it up to authenticate against our windows AD.
What I like about OTRS is that it can integrate into Email AND Web. So users can email in a problem, it will open a ticket, and then you can log into a web interface and answer them back to their email. If the user wants to use a web interface 1/2 way through, they can... and everything that they emailed back and forth is stored as notes. Its all seamless to you and the user.
You can also have 'canned-responses' so you can email a user or put a note in a ticket without typing everything again.
OTRS also has a FAQ section, where you can put a 'how-to' section. It also can reg-ex certain words and put them automatically into different queues.
Software: for Software bug tracking, (the place that I am now) we use Mantis BT. I would say its very easy to use and setup, we authenticate against an openldap server.
BugZilla seems to be a popular choice.
An alternative to Bugzilla/Redmine is Mantis Bug Tracker.
If yours developers are using Eclipse, you should take care of a good integration with Mylin, a wonderful eclipse plugin to access to yours bugs directly from Eclipse and also link source code to them.
I know that Bugzilla and Jira (very good but not open source) are currently supported.
Roundup is pretty good, and easily hackable with a bit of python knowledge.
check out JIRA, really good for help desk as well
I'm currently using a product from a company that rhymes with "Bog Peak" at work for issue tracking. I like it. But not open source, so it doesn't answer your question.
I don't have anything to recommend from personal experience, but I can speak out against two earlier suggestions: Bugzilla is a nightmare for non-technical users, and Mantis is a steaming pile of usability fails. Not a fan of either at all.
I've heard good things about Trac and Lighthouse. (Although Lighthouse doesn't really qualify as open source, it does provide free options.)
If you haven't given up on the Trac approach, you might want to look at http://trac-hacks.org/wiki/SimpleTicketPlugin to hide some of the existing fields. Note also that if you remove all options from many of those fields, they'll vanish from the UI.
Also, with Trac 0.11, we have configurable workflows. While most often used to add more states to a ticket's path from "new" to "closed", you can reduce the workflow to the point that those are the only two states.
One of the issues with most trackers is that they drive clients away on first sight. I highly recommend Snowy Evening, because it's just as powerful as these others but is also extremely easy to use for my clients:
http://snowy-evening.com