Starting a new business... need advice on LLC's and contracts

I am going to be starting an independent consulting firm for Microsoft applications. I am going to be focused in programming automation code for Excel, Word, Outlook, etc. and I have a few questions surrounding this.

1. Am I going to have to become licensed through Microsoft to do this, or will I be able to build code to automate processes without having legal ramifications from Microsoft?

2. I do not want to be liable if a client changes the coding that I provide to them. Is this something that can be covered in a contract/waiver, or will I need to become an L.L.C. to protect my personal assets?

Any help on this will be greatly appreciated!

Depends on how you are accomplishing this. If you are writing stuff for the clients directly and they've installed the appropriate packages on their machine then you don't need Microsoft. If you need to use one of the automation SDK's and redistribute the necessary dll's or assemblies, then you need to get the appropriate package (or MSDN membership) from Microsoft that gives you the redistribution rights.

You can write waivers but chances are they won't stop you from being sued. An single person LLC won't do much for that either, though it may be advantageous in other ways which aren't so much legal but financial. I'd recommend getting smart through some small business program offered by your local government, community college, or often at public libraries.