Admittedly I'm enamoured by the idea of a GPL C# IDE written in C#, but here's another project that works with Eclipse as a plugin. It's written in Java, which is an interesting mix (Java for C# dev), but Eclipse is a fairly responsive IDE for Java that I used on my last Java project that didn't require a GUI.

Most of my day job uses a set of COM-based apps, so for the most part I don't get to do any C# jive unless I force a reason, but this "esharp" plugin strikes me as a little out in left field. I wrote the author on the off chance he hadn't heard of #develop. His reply amounted to this esharp plugin for Eclipse allows people to develop on Linux for C# via the Mono project's C# compilers. Last I'd looked at Mono, it was only good for a few simple console apps, and had just gotten to be self-hosting on Linux. Not exactly a pressing need. And once Mono is mature, it should run #develop right out of the box!

Head to the Mono project website now and you'll see a different picture. Windows.Forms is starting to develop. The project is looking for someone to hack up "an ASP.NET application to maintain our class library documentation". They're even branching out to get VB.NET to compile and work with Mono in the future, though I didn't think VB.NET was in the standards proposal Microsoft submitted when it submitted C#.

Neat stuff. And since #develop still doesn't have a good Windows.Form RAD, the esharp plugin might have a good niche for building console and ASP.NET apps until Mono finishes Windows.Form.