If you setup your laptop in a workgroup (say MSHOME) open control panel /
user accounts, select your account and select manage network passwords.
Then you need to add one or more entries for the domains for the resources
(computers) you need to access. Say your company's internal network is
"foo.net". All of the resources you want to access will be on
<somehost>.foo.net. Say your account at work is "foo\kevin". You would add
an entry in saved passwords for "*.foo.net" with a id of "foo\kevin" and
your domain password.
Next, if your DHCP server at work doesn't automatically hand you the domain
foo.net when it hands you an address you add foo.net as a completion domain
in the TCP/IP advanced settings on the DNS tab (DNS suffix for this
connection and add these suffixes in this order).
Finally (phew this is getting long), you want to make sure that you enable
automatic logon in the "intranet" zone and ensure that "foo.net" is
automatically listed as intranet.
You do that in IE7 (Tools/Internet Options/Security/Local
Intranet/Sites/advanced). Make sure that "*.foo.net" is in the list. Also
select "Custom" for the security settings for the intranet zone, scroll down
to "authentication" and make sure that automatic login in the intranet zone
is enabled.
That should do you.
Now, since you're in a workgroup your home based resources will work the way
you would expect them to and when you're at work you'll be able to
authenticate to the domain based resources in "foo.net" using a set of
cached credentials that you've manually stored.
Couple of caveats: First, you won't be able to search for printers at work
(that requires a machine that's actually joined to a domain and you won't
be). Actually, you won't be able to use any of the search features that
search the domain (printers is about the only one that folks use so it's not
a big loss). Second, when your password expires on your domain you need to
change your password from a machine joined to the domain (you won't be able
to do it from this machine since it's not a domain member). Next, domain
based login scripts won't execute for you (since you never actually login to
the domain), so you map your own drives and/or printers. Finally, when your
password changes you need to go back into control panel and update the entry
for "foo.net" with the new password and answer NO when Windows asks if you
want to change it on the domain (since you're not in the domain it will just
fail anyway).
If all of the above seems too complicated, just have your machine joined to
the domain. You can still access shared resources on a workgroup computer
(you just need to create a local account on both machines so that you can
properly make the connection).
Best of luck.
J