One of the big disadvantages to using Blogger (as opposed to many other blog tools) is there is no easy way to post entries into categories. It's been bothering me for some time, so I finally gave in and set myself up on del.icio.us.
It's unlikely that I'll try to go back through 300+ entries and get them sorted, but I'm spending at least some of today working back through the last month or so. (sigh...)
I've added a "Categories" link to the left nav column. Let me know if it's helpful, or you notice some obvious taxonomy I'm overlooking.