Take a look at the follwing screen shots for ideas:

http://www.members.shaw.ca/AlbertKallal/Articles/Grid.htm

In the above on quite a few of the sample forms, you can see that I placed a
little button called "edit", or a buttion with the glasses icon.

when you click on that button, then you have full access to the record and
you can pop open another detail formed with the following line of code

docmd.Openform "frmCustomers",,,"id = " & me!id

You didn't really give much information as to what you want to do when you
select that one row to get the ID, but the above is the general approch used
in those sample screen shots...

Some people actually don't place a button on the form, but the double click
event on the text box control, and thus double clicking on the text box will
launch the detail form that a lousy to edit the information in a form.