I strongly urge you to have a lawyer draft a document for you. Are you selling your interest in the LLC or giving it to the other couple? What does the company do? Have you made any personal guarantees (i.e., on loans, etc.) during the course of your membership in the LLC? If you are selling your interest (and if that is permissible under the LLC Agreement), you should have an attorney draft a Purchase & Sale Agreement that limits your liability and details the specifics of the transaction.
On an unrelated note, I was just in Anacortes this weekend on my way home to visit my folks in the San Juans. Love your town.
I strongly agree with Valerie Ann Farris in her recommendation that you consult with an attorney to have a legal document contemplated and prepared for this transaction... and not just because I'm a lawyer :).
Transferring ownership interests in an LLC to another party is a rather complicated transaction, and as you suggest, you'll certainly want a legal document prepared that limits your liabilities to the new owners and to the company itself.
To accomplish a general transfer such as the one you've described, I'd suggest:
1) Reviewing the Operating Agreement (if there is one) to determine how Transfers such as this can take place, and proceeding as per the OA.
2) Amending the Articles of Organization to change the ownership interests as per the transfer.
3) Drafting and executing an "Assignment" document, whereby you "assign" your interests in the LLC to the new interest-holders.
While there are circumstances where business owners may file form documents with the secretary of state and other agencies without the advice of counsel without high risks of complications, this is certainly not one of those circumstances. There are a number of things you should consider in executing this transfer of interests, and there are a number of complications that may occur if something is overlooked.
Just to expand a bit on the existing answers: It sounds as if the "different couple" you are contemplating a transfer to are third parties and not the other couple that currently own membership interests in the LLC. If that is the case, your transfer may require the approval of the other members.
You should definitely consult with an attorney in your area to review the operating agreement and make sure all the I’s are dotted and the T’s are crossed correctly. Most likely an assignment will need to be prepared, along with a consent of the other members and an amendment to the company's operating agreement.