Is there a recommendation on referencing the new CSS files for a partner developing a composite application?

Option 1: external reference to the CSS files hosted by salesforce.com?

or

Option 2: download CSS files and host them ourselves as part of the composite app?

Thanks

I'm building a website for a small company that uses Salesforce and they would like to include a "Contact Us" form on their site that submits the user input to Salesforce.

Is this possible?

If so, is there any existing documentation on how to do this?

I searched the Salesforce "Help" section but only found a few brief references to "Web to X" and "Web to Lead" forms...nothing very instructional.

Thanks in advance for your help!

BC