If you want more control over how Yahoo spiders your site, then you need to read this article on wild cards.

If you are interested in keeping up with what is happening with Search Engines there are a few blogs that every webmaster should read.

Googles WebMaster Central

Matt Cutts Blog

Yahoos Blog

MSN Blog

If you want to keep up with general information about Google, and whats new then I would add the Google Blog

You will get a lot of helpful information that can help you with the SEs, if you read these blogs.