On NETTUTS.com today there's a tutorial (a screencast) that'll show you how to create excerpts for the posts in your blog. Their method could be applied to just about any PHP-based blog software out there since it uses base PHP functions and MySQL features.

Ever visited a blog, and noticed that each posting's overview only contained a hundred characters or so, which is then followed by '�'�'�? Ever wondered how to do that yourself? It's not quite as easy as you might think. What if character number 100 occurs in the middle of a word? Do you want to display half of a word on the page? Of course not. In this video tutorial, I'll show you how to compensate for this, as well as a host of other neat little things, like working with MySQL's LEFT() function, using PHP's strrpos, and substr, creating the beginning's of an actual blog, and more.

They show you how to use the MySQL LEFT() function, strrpos and substr to make creating these summary blocks of text simple.