Several years ago we took out a $15K loan using our home as security. We now owe about $6K.

If things get more hairy with this economy:( and we can't afford to paythe $300+ monthly payment for awhile, can the bank take our home, or will it just slap a lien on it?

Depends on the terms of the loan. If this is a mortgage, then it's a non-recourse loan which means that the bank's only method for coming after you is to foreclose on the house - then that's what they'll do.

But before it coms to that - if the loan balance is down to $6K, you may be able to refinance with a new 10-year equity loan and get the monthly payment down to half of what you're paying now.