NoteFly (http://www.notefly.org/) is a FOSS skinnable sticky notes manager with syntax highlighting, which is allegedly portable (see below; untested!) so here's a post for it...
DotNET requirement is v2.0.
[url]http://www.notefly.org/[/url] author wrote:NoteFly is a opensource, ligthweight, highly customizable, with advance features note taking application for windows.
Untested so far but I like the customization. I hope the author adds some default color or skin options that are a bit more on a theme. So pastels, textured, glassy, etc.