The 2 examples are minified versions served from popular CDN, so many visitors will have them in their cache, and therefore no HTTP request will be required.

If you want to combine them, download the files and then you need to do some kind of combining the files on the server side. If you are using .NET SquishIt is a popular choice. If you use PHP minify is an option.

In regard to the CSS files, the above two options support those as well.