Is Ubuntu branding with other Linux Distro logos OK?

So I'm organizing a Ubuntu Hour, and advertising it through both the local LUG and the loco team - what's the policy regarding the Ubuntu logo on a poster with other Linux distros? (Fedora, Debian, Arch etc)

If it's non-commercial, no problem. The trademark policy should allow this. If there's any doubt, you can email your plans to Canonical and you'll get a straight answer in writing. Here's the relevant extract:

Community advocacy. Ubuntu is built by, and largely for, its community. We share access to the Trademarks with the entire community for the purposes of discussion, development and advocacy. We recognise that most of the open source discussion and development areas are for non-commercial purposes and will allow the use of the trademarks in this context, provided:

• the Trademark is used in a manner consistent with the Usage Guidelines below
• there is no commercial intent behind the use
• what you are referring to is in fact Ubuntu. If someone is confused into thinking that what isn't Ubuntu is in fact Ubuntu, you are probably doing something wrong
• there is no suggestion (through words or appearance) that your project is approved, sponsored, or affiliated with Ubuntu or its related projects unless it actually has been approved by and is accountable to the Ubuntu Community Council

To keep people at Canonical happiest, you could adhere to the branding guidelines here:

• http://design.canonical.com/brand/B.%20Complete%20Ubuntu%20brand%20guide%20-%20November%202010.pdf

They are design guidelines so aren't legal-issue-aimed but you'll find out the way Canonical wants things branded. For the Ubuntu Logo, you want page 38 onwards. You'll see how much space you need to give it and what you are allowed to do in the way of editing it (not much!)