gnuais 0.1.0 can now be downloaded from SourceForge. It's an AIS decoding program for Linux, licensed under the GPL. Attach it to the 9600-bit/s data capable discriminator output of a VHF FM receiver, tune the rx on the marine VHF channel 87B (161.975 MHz) or 88B (162.025 MHz), and you'll be able to receive position data from nearby vessels.
Version 0.1.0 has an improved DSP decoder (thanks to Tomi Manninen, OH2BNS) and it can also upload AIS data to aprs.fi using the new JSON AIS protocol. If you wish to share your AIS data with aprs.fi, please drop me an email - the address is on the Profile page of this blog.
This is still an alpha quality release, so there are some caveats - the local GUI isn't working, and SoundChannels should be set to both (other settings will probably not work). The installation instructions are not very good either. If you've compiled software on Linux before, set up an igate, and played with soundmodem or gmfsk, installing should be pretty easy. It's an open-source project, so contributions are welcome!