Not sure what the exact issue would be. The email cheching you're looking at in another thread would probably be the issue when it was one blog per one email address.
The issue is that each user account is tied to a single email address and two account do not have the same email address. You can create the blogs yourself at Dashboard -> Site Amdin -> Blogs -> Bottom of the page. But they would be tied to your account and be given Site Admin access.
I really can't think of a way around this. You can use a second email address for a second account for yourself and create those accounts that way but they still would have access to each others accounts.
Only thing I can think of is creating accounts using dummy email addresses in the Dashboard -> Site Admin -> Users -> Bottom fo the page. If you yourself do it there, there's no checking on the email address that I know of, each student would have a seperate account, and they themselves or you could create their own blogs with those accounts.
Hope this helps,
-drmike