I have looked at a few posts that state the need for Visual Studio 2008 in order to run F#.
Is there a simpler tool (maybe in interactive mode such as Ruby/Python) to learn F#? I have the Visual Studio Express edition on my machine.
Your suggestions are welcome. Any good links (for a C# developer) to get started are welcome as well.
If this is already asked, I apologize. Please point me to the link to the original question, if so.
The MSDN download page states that VS2005/2008 are optional. When you download the zip file, the readme talks about fsc.exe (the compiler) and fsi.exe (the interactive compiler). I haven't yet installed it myself, but it very much sounds like these will get you going with no problems.
You can use Visual Studio Shell (integrated mode) which is free. The F# setup will install what is required for you to use F# in Visual Studio Shell. I think Visual Studio Shell is the best choice right now. It's got all the Visual Studio goodness and the flexibility to do your prototyping and scripting.
As for learning resources, the 'Learn F#' page on MSDN isn't much help right now. The F# wiki by Robert Pickering is a good place to start.
For more advance tutorials you can check here.
To answer the other part of the question: Express versions of VS will not do if you want to use F# from within VS. (You either need a full edition of VS, or else the free VS Integrated Shell.)
You can just download the zip and use fsc.exe and fsi.exe from the command-line, but personally I would recommend using VS for a richer experience.
If you're on Windows, install VS2010 Beta 2. http://msdn.microsoft.com/en-us/vstudio/dd582936.aspx
If you're on Mac or Linux, just install mono and the F# compiler.