There will be times when you will want to keep a post at the top of your blog. This could be because you are hosting a blog candy, or looking for a design team.
Again, this is very easy.
Type up your post and publish it as normal. Then go into the Edit Posts page and reopen your post. Scroll down to the bottom of your post and click on Post Options. Click in the circle button next to Select Date and Time and type in the date and time until when you would like your post to stay at the top. If you don't know when you want to keep it there until, you can add a random date sometime in the future - you can always go back and change it later on to an earlier date so it will continue to fall down the page as normal.