Passing ArrayList into Sql Query or any other way around

Hi

I have an arraylist that contains the names of those userid's that i need to check in an online db to check out if they are online now.
If the UserId column of the SqlTable matches any of the name of that of the arraylist, then i need to import the values of two corresponding fields say age, Nick etc.
I would be very grateful to anyone who could kindly tell me how to do this in an Sql Query i.e How to actually send an arraylist into sql query or any other way around this problem.

Say the arraylist to be verified against the table is:
public ArrayList BuddyList = new ArrayList();

Thank You.

Regards.

Check this, it would treat your issue in different way
http://weblogs.asp.net/pleloup/archive/2003/04/14/5569.aspx
HTH