How can I get my central Blog page to summarize my entries?

I have seen other Blogs where the list of blog entries are summarized. However, on my Blog, the entire entry is shown.

I would like my central Blog page to show the title and a summary with the first few sentences only. If the viewer wants to read the entire post, they can click on the link to see it.

Here is my Blog so you can see what I am talking about:

http://robcaldwell.net/blog/

Thanks,

Rob Caldwell