The Exchange admin tool only allows you to choose one name at a time
when creating Distribution List (DL's).  How can I (or what software
will allow me to) create a DL with a bunch of names from an Excel
sheet.
Thanks in advance.
Steve

Dear stevenclary-ga,

You can achieve this by using the "Directory Import" feature in the
Exchange 5.5 administrator.

My initial discovery was a solution to the problem of adding multiple
users to an existing distribution list, given in the Microsoft
Knowledge Base:

"To add only mailboxes to a DL in the Recipients container:

1. Create the DL that will hold just the mailboxes (for example,
Mailboxes-DL).
2. Add just one mailbox from the Recipients container to the members
list in the DL.
3. Perform a directory export of just the mailboxes from the
Recipients container.
4. Open the .csv file in Microsoft Excel, and view the Members column
for the mailbox you added to Mailboxes-DL.
5. Copy and paste the CN name for the DL (for example,
%Recipients/cn=Mailboxes-DL) to the rest of the mailboxes in the
Members column so that all mailboxes that you want add to the newly
created DL have the CN name.
6. Save the .csv file, and then perform a directory import of all of
the mailboxes and make sure that the multivalued properties by default
show append before proceeding.
7. After you have completed the directory import, you can see that all
the mailboxes are in the newly created distribution list."
  - XADM: How to Add Only Mailboxes to a Distribution List (241195)
    http://support.microsoft.com/default.aspx?scid=kb%3Ben-us%3B241195

This would at least speed up adding large numbers of names to a
distribution list. Creating one from scratch, however, is somewhat
more complicated, but I have been able to put together a description
from a number of sources regarding how to do it:

1. Create an Excel spreadsheet with the following column headings
(commas indicate moving to the next cell):

Obj-Class, Display Name, Alias Name, Directory Name, Members

Populate the columns below these headings with the information on your
distribution lists and the users who are members of them. For example,
if you had two distribution lists List A and List B, the former
containing users Celia, Derek and Ed, and the latter containing users
Celia and Fred, the next five rows of your sheet would be as follows:

DL, List A, List A, List A, Recipients/cn=Celia
DL, List A, List A, List A, Recipients/cn=Derek
DL, List A, List A, List A, Recipients/cn=Ed
DL, List B, List B, List B, Recipients/cn=Celia
DL, List B, List B, List B, Recipients/cn=Fred

(Again, commas indicate moving to the next cell; this also assumes
that all your Users are in the default Recipients container.)

Save the sheet from Excel as a .CSV (Comma-delimited) file, rather
than a .XLS, and import it into Exchange as follows: in the
Administrator program, click Directory Import on the Tools menu. Leave
the settings at the default settings, click Import File, and then
select the appropriate .csv file.

When this import is finished, the distribution lists should be created
and populated.

Additional Links

XADM: Bulk Import/Export FAQ (155414)
http://support.microsoft.com/default.aspx?scid=kb%3Ben-us%3B155414

XADM: How to Create Mailboxes by Means of a .csv File (244595)
http://support.microsoft.com/default.aspx?scid=kb%3Ben-us%3B244595

XADM: Can't Import Nested Container Recipients into DL (165319)
http://support.microsoft.com/default.aspx?scid=kb%3Ben-us%3B165319

If this answer isn't quite what you're looking for, please feel free
to request a clarification,

cerebrate-ga

Search strategy:

Microsoft Knowledge Base - "distribution list" and "Exchange directory
import"