37signals today announced the release of BackPack, a Web-based personal and small business information manager. “Backpack makes it easy to flesh out your ideas. Start with a title: “My trip to Paris” or “Wedding planner” or “Business name ideas,” and so on. After you’ve created a page, you can add a to-do list, or notes, or photos, or attach files, and more. You can even send an email to the page and it will automatically be posted to the page.” Backpack comes in 4 flavors: a free version, to US$5/month, $9/month, and $19/month for the top plan.