Wikipedia can do a better job of explaining a blog than I can. It is rather long so you could probably just skim the article.
http://en.wikipedia.org/wiki/Blog
There are about a zillion blog sites on the Internet and most all are free. Blogging is extremely popular. I am in love with everything Google so I will recommend
http://www.blogger.com/
It is actually pretty easy with Google. If you don't have a Google account then sign up for one, it is free. Then go to blogger.com and log in. There is a button on the left that says "New blog". Click on it and it will walk you through the steps to get started.
With a blog you can write an unlimited amount of text, you can add photos, video or audio clips to the blog. The best thing for you to do is to do a search on this forum for "blog" and find someone here with a blog and then go check it out. Check out at least a half a dozen to get an idea on how other peoples blogs look.
Once your blog is functional then you give the address to your friends and family and they can keep up with your every move.
