I made Trunk as an Evernote alternative. It's open-source and web-based, using Markdown to store notes. It might be too simple for your needs however. You can

I made Trunk as an Evernote alternative. It's open-source and web-based, using Markdown to store notes. It might be too simple for your needs however. You can try it at http://trytrunk.com/ http://trytrunk.com/ or get the source at https://github.com/timdavies/trunk https://github.com/timdavies/trunk