Instead of XML, I'd recommend a database. The reason is because it'll be much easier to remove entries from a database than XML.
You'll also need some form of server-side scripting language. I'd recommend PHP (server-side scripting language) and MySQL (free database server).
If you've never done any of this before than you have a good deal of work ahead of you. =)
First you'll need basic HTML.
You'll need PHP and MySQL for the Linkedin stuff and pulling out the information.
I recommend picking up some books on each topic. Sitepoint has some good ones. There are also lots of free tutorials all over the web.
If you let us know about your experience we could probably help you pick a decent starting point.