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
Obfuscation should never be confused for security.
.NET Reflector makes it pretty straightforward to reverse engineer most .NET code. You may not get pretty variable and method/method parameter names, but anyone interested in reverse engineering your intellectual property will have enough information to do so.
If you need stringent protection of your intellectual property, consider taking critical parts of your code and only exposing them as web services. Alternatively, consider tools like HASP that add a level of encryption and anti-debugging/reverse engineering protection to your product.
If neither of these is possible ... consider hiring some good lawyers.