Yes there is an insert code button in the editor however you may notice that if you paste in 300 lines of code, or code with long lines that readers will have to scroll the little scrollbars to read it well.
In general we prefer only snippets of code in the forums - the FAQ suggests 20 lines maximum but its really up to you. You will probably find that people can read, and therefore understand and therefore respond to your code better if you use a pastebin for the larger snippets.
Suggested locations:
http://www.rafb.net/paste/ http://pastebin.com/ http://xna.multigan.com/pastebin http://pastebin.ca http://xna.pastebin.ca
