MountainDesk 1.002 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The actual developer of this Mac application is 37signals. According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software.
From the developer:
MountainDesk is an application developed in Flex and deployed via the Adobe AIR platform. Once you launch the application and sign in to your account, the aprogram immediately starts to retrieve your data from Basecamp. You can now work just like you would normally using Basecamp while all your changes automatically stay in sync.
Furthermore unlike regular basecamp, you can continue to work even when there is no internet connectivity.