(Last week Mary Ann asked for this tutorial so here it is!)
Numbered comments are great if you're hosting a giveaway or blog party because it is that much easier to pick a winner by number. =)
First things first, numbering comments only work if they are embedded below your post.
1.) Go to your dashboard > template > edit HTML > and click 'Expand Widget Templates'
2.) Search for this code:
<b:loop values='data:post.comments' var='comment'>(I suggest using find option on your browser: Ctrl + F)
3.) Above that code paste this code:
4.) Search for this code:
5.) Below that code paste this code:
As always, if you have any questions--ask away!