Hello Philip,
AFAIK, Blogger doesn't have a function that allows posts to be truncated on the front page with a link to continue reading the entry. You'd need to jerryrig a solution; if you're trying to do this for more of a SEO benefit, then this
CSS solution may not be ideal, however, if you're doing it for reader benefit, then it may work for you.
Maybe one day Blogger will step up and start allowing excerpts for its blog entries. :/
~ Teli