Here is the UKBA webpage for application forms for visas for partners and other family members with a view to UK settlement

The needed forms etc are all listed on the right hand side of the webpage and available for download.

Could be a good idea to download them now as they may not be available as a direct download once the online submissions systems are up and running smoothly.
It's always good to have a paper copy for reference anyway.

Worth looking at the links to better understand how the new immigration rules will impact all new entry visa applications