There are two ways to create voice
emails from within Blackboard. This
description is of the most common way.
First, login to Blackboard and open
one of your Blackboard courses. From within
Blackboard click on the Communication link on your
tools menu:

In the Communication area click on
"Voice Emails":

You must now select recipients from
various groupings:

Depending on your selection, will
see something different. Supposing you select
the final one above, you will see a list of everyone
enrolled in the class, with a check box next to each
name. Place a check in the box next to those
you wish to send a voice email to. Then click
submit:

The voice email form will open.
Type a subject (required), add text, if you wish,
and then click the Record button:

A recording level meter will appear
as you record, and the elapsed time of your
recording will also be displayed. You may
click the Pause button during recording and then
resume if you wish. When done, click the
square Stop button.
Clicking the Archive button will
show archives, if any, of previous emails.
Click the Send button when done.
The voice email will be sent immediately.
The recipient of a voice email gets
an email that looks like this:

When your recipient(s) click the
play link, they will see the voice player embedded
in a web page:

Clicking the Play button will play
the message. Clicking the "Save audio file"
link will save the file locally as a wav file.
Clicking the drop-down at the lower right of the
screen opens a "Save As" menu which allows saving of
the file in one of three formats:

There are three file formats in
which the recording can be saved:

mp3 is the most compressed, and
therefore smallest, file.