Just a little note to say that:
It's had a UI overhaul, and I've added accessibility support to the custom widgets (and improved it for the rest of the interface too). It's primarily intended for use in schools in the UK who teach A-level electronics, but I suppose it could be adapted to work for other purposes. It can be downloaded as a tarball (source), NSIS installer or ZIP package (for Windows).
Here's an announcement I've wanted to make for a while: I'm releasing my microcontroller simulator, MCUS. It's a fairly simple simulator designed to aid in teaching the OCR 2008 A-level electronics syllabus to UK students. As far as I know, it's the only simulator available which follows the new syllabus (for which OCR have deigned to write their own simple assembly language, obsoleting any previous simulators used in schools).
It's already had three releases (this is the fourth), but I didn't want to make the 0.1.x releases too public, as they were mainly for testing the program at school. The 0.2.0 release was a brown paper bag release, due to a bad GTK+ version dependency, and some files necessary for the Windows zip package not being included.
It's available on the MCUS project page, with 0.2.1 being the latest release. A Windows installer is available too, built with NSIS; as well as a simple zip package of the installed directory tree on Windows, since the program's relocatable.
My school is already using it, and I'm releasing it in the hope of other schools being able to make use of it. As always, it's open source, released under the GPLv3+.
Future plans include a graph to visualise the ADC waveform, and the addition of more simulated input and output hardware.