It is possible to make a friendly url that points to a blog post using the Administration > Url Manager.
For the friendly url you would put:
~/mypostaboutwhatever.aspx
and in the real Url you put this format:
~/BlogView.aspx?pageid=2&ItemID=8&mid=7
There is nothing automatic to do this. You need to be careful to avoid name clashes with real pages or other virtual pages.
Hope it helps,
Joe