I've just released AnsiGo, a simple ANSi to PNG converter written in pure Go : it simply takes an ANSi file as input and converts it to PNG. No external dependencies are required (the font data is embedded) and AnsiGo compiles into a single binary file. At the moment you will have to compile it yourself, but I hope to provide binary versions and a Windows executable in the future.
Edit : precompiled binaries for Windows (both 32-bit and 64-bit) are available on the repository.
AnsiGo 1.00 (c) by Frederic CAMBUS 2012
USAGE: ansigo inputfile
EXAMPLES: ansigo ansi.ans
The project is hosted on GitHub : AnsiGo