There are a few programs on the market that you can use to obfuscate your .net code, my question is, how easy is it for someone to get at your IP if your code is \"so called
This completely depends on the Obfuscator.
Obfuscation, in general, does a very good job of making it much more difficult to reverse engineer - but it doesn't prevent it by any means. The CLR will always need to decipher the obfuscated IL, so a dedicated person can always do the same.
However, most software licensing and protection really does two things:
Obfuscation (combined with a proper licensing scheme) prevents both of the above very effectively. It changes a simple procedure to a much more complicated task.