auto <p> tags generated for posts? Where?

Hello. I am using wordpress both by calling the loop from within my own xhtml pages and as its own default blog.

I am trying to use Blogdesk as my weapon of choice to write posts. I noticed a big problem (perhaps an issue with my blog /css settings or with blogdesk).

When I type a post in blogdesk it will typically insert tags at the start etc. What I am noticing is wordpress is also _automatically_ adding tags for the post content.

why and how is wordpress doing this? I would like to turn it off somehow so that I can control the markup better. As a result I get double <p><p> tags that mess up my xhtml validation.

Thanks.

ps.what do you guys use to write your posts most of the time?