The business model canvas gets mentioned a lot in lean/start-up circles. Here's my quick review of 8 of them.
The current best-list of business model canvas tools is located at http://leanstartup.pbworks.com/w/page/47250326/BusinessModelCanvas.
A free tool, embeddable on blog or web-page, highly interactive UI, good clues/info-tips on the various sections.
Also free and based directly from Osterwalder. This is a very attractive JS based UI, pretty colours, good prompts for the section data, excellent highlighting/diff viewer. Markdown support.
Free, only requires email (but fakes accepted). Multiple canvas templates (business model, lean, swot, customer journey) to choose from. A very awesome and unique canvas history replay tool.
This is an actual, tangible kit for purchase. It comes with magnetic icon blocks that you can stick to surfaces and then draw on. They also have links to some super awesome examples around companies you've heard of (Spotify, Groupon).
The original, a big PDF to download to help you get started as well as an iPad application. A web-application is in the works.
This one is a WordPress plugin, if you're already on WP why not give this one a try? It's currently invite only beta.
This one provides a nice canvas UI, between $12 and $49/mo and a two person free plan. The Lean Canvas based on the Osterwalder canvas.
Free for a single user, then plans between $9 and $99/mo. Allows for multiple projects, multiple collaborators. LLL also provides more tools than just a canvas. There are some good tools for experiments and customer interviews for example as well as team communication tools.
Not so much a canvas but a quick plan/model builder; has some very plesant icons to add to the model. Produces a PDF document of your Idea, Team, Product, Revenue, Funding Goals and Partnership. I think this is turning out an executive summary and does really help you focus on the message (with "tweet length" limits)
update: dropping this canvas tool - use bmfiddle!
This last one is ours, just made it while working through Start-Up Owners Manual. It has a typical canvas layout, allows for markdown input, exportable as markdown as well. Canvas is free and can be shared widely with your collaborators. Our UI is a bit more limited than the others.