You probably want to look into
Multiuser access[
^] for a good starting point.
As for the second question, I don't believe so, but you may want to check out LocalDB. See the following links about LocalDB:
MSDN Magazine (at the bottom)[
^]
Release annoucement[
^]
LocalDB Q&A[
^]
I haven't been following this that closely, but dig around a bit for it and see what you think. It may apply to your situation.