We use the Trac wiki for:
- List of requirements for each feature
- List of technical specs (if any) for the features
- List of Releases and their features
- Deployed environments, with links to all instances
- There's a macro for making web requests, so we can list which version, etc. each env have
- (there's a GraphViz plugin which is quite helpful for simple drawings)
There's also a ticket in the ticketing system for each "feature", for keeping a gross backlog and the current/next sprint planned.
Then we write a bunch of cards during sprint planning for each feature.
There's also a more operational side to things. We keep one person each sprint on Ops, so we have one person who's dedicated to be interrupted by people outside the team. The rest of the team can focus on delivering features.
Each bug/ops task gets a ticket, but as soon as we start working on it, it gets a card and starts moving across the board. That way it gets visibility and we don't forget to involve the testers, etc.
Scrum is pretty tactile, so I don't think it would work great to put too much stuff outside of the physical working environment. But in the end your team needs to find a balance that works.