Unix command(s) to eliminate file extension?

[Rodolfo Medina <rodolfo.medina@gmail.com>]

Hi.

Suppose I have in a directory a certain number of files,
all terminating with `.txt', and that I want to eliminate
that suffix from all of them.
Is there a Unix command, or perhaps a set of commands,
that can do so?

Thanks,
Rodolfo