There are plenty of tools and services that provide this type of product.

Forum Submitter Service

That just doesn't sound Kosher to me. Submitting anything to forums from an automated routine is most likely against the TOS of those forums. I'd like to suggest caution in the use of these types of products.

I believe there are link services that also provide this method as an option.

P.S. Due to WebmasterWorld TOS, you won't get any specific recommendations out here at the public level. I can assure you, there are more likely over 1,000 resources out there that perform or provide something right in line with what you may be looking for.