Since switching to the Beta Blogger template -- which, by the way, I really really like -- I've discovered that there are problems posting comments.
If you have a Blogger account but have not upgraded to the Beta, you may not be able to post comments to a Beta blog like mine. The opposite also appears to be true, as I've not been able to post comments to some non-Beta blogs with my Beta account. Hopefully Google/Blogger will get this all worked out.
*** Update 09/23/06 -- The beta bug is fixed. Everyone should be able to post comments now. ***