Here are some tips to get you started! For integration with other systems, you have two tools:
FogBugz has a comprehensive XML API you can use if you want to customize the other system to talk to FogBugz.
Use FogBugz webhooks to trigger your own script on a variety of case events.
For Licensed FogBugz
The plugin architecture lets you add and change functionality in FogBugz itself. You can use this to change the UI for users, and you can also use it to get FogBugz to talk to other systems.
For example, you can have it hit specific URLs on different events (this exists already in the URLTrigger plugin, though it isn’t yet available for on demand accounts)
Or you can have FogBugz perform specialized tasks periodically in the background.
You can also use the architecture to create new externally accessible interfaces for another system to interact with (if the existing XML API doesn’t do everything you need)
For FogBugz On Demand
Due to large architectural changes that are in progress, we are not currently accepting new plugins for our FogBugz On Demand platform.