I have been searching for help, can't seem to find my exact situation...maybe someone here will read this and offer suggestions. I will try ot be brief.
I've had dogs all my life, and several times have brought a new pup home to the adult dog(s) and never had a problem.
I fear I may encounter a problem this time.
We have two dogs...a 9 yr old Black Lab, Emmett...he will be no problem with the new puppy...I am certain of that...especially that he welcomed our youngest dog into his life less than 2 yrs ago.
The youngest, Arwen (a rescue) is 18 months old, spayed female. We beleive she is part German Shepard, part Dobie...and may have some mystery breeds tossed in...she is a very good dog, adores Emmett, loves our inside/outside cat, plays gleefully with my brother's Lab.
One thing she does do, we are working on this...she'll get very aggressive of dogs she sees when in the car...otherwise...she is no problem.
I do know for sure, she is going to be very jealous of the new pup ( 6 wk old male Black Lab)...and for the first time in my life, I cannot predict how one of my dogs is going to behave...I'm not sure what Arwen will do.

We plan on introducing the pup to Arwen in the backyard...not sure yet if Emmett will be present...I am not sure if we should allow him to be there, or in the house...only because Arwen may get jealous if Emmett pays attention to the pup...we will keep Arwen on a leash. As long as it goes well outside, we'll move into the house because that is where Arwen would become posessive.

I could use any suggestions that might help me to get this right.

Thank you.

Have you read Ed's articles and FAQs on introducing dogs?

http://leerburg.com/introducingdogs.htm

6 week old pup? Can you leave him/her with the litter for two more weeks?

Joannie, Aaron gave you the guide that best fits your immediate situation. Leerburg's DVD Pack Structure is highly recommended in the long run.

What's the phrase? "Two's a pair, three's a pack?"

In the short term, you should assume that your adult dogs will eat the pup if you leave them alone, and manage the situation accordingly.

There is no hurry to developing a "happy family." You will not regret moving slowly and methodically through the steps, even if it seems as though everyone's happy and all is good.

My otherwise docile lab, about the age of yours, laid our dachshund's shoulder open to the tune of about 35 stitches years ago. They were together only a few seconds, and by mistake.

If you are cautious and methodical, you can make it work. Just don't get impatient and assume that tail wags in one moment won't turn into fur flying the next.

Lord. I missed the 6 week old part.
::facepalm

Don't introduce them right away. Crate the puppy and let Arwen and Emmett get used to him being there. Read more of the articles here for more details.

So did I.

I just want to say a huge ditto to Rob, too. Three dogs = a pack. Two dogs and three dogs are not even remotely similar, IMO.

The everyone-frolic-together thing is a goal (if it even IS a goal) that can and should be very long-term. No immediate intro at all.

Ed's protocol is spot on. I would not skip anything or hurry it along at all. A bad start will taint the whole thing, maybe forever.

I have to agree with Connie and Ron, Three dogs= pack. The dynamics changed dramatically when my girlfriend moved in with her one dog in with my two dogs. We both say we will not do 3 again. As one dog trainer once told me, you should only have and walk as many dogs as you have hands. I walk all three together, but it is much easier with two.

I too would refer to Ed's advice. One thing you may want to try when you do finally introduce them is to do it on at a neutral location, not at your home or in your backyard. This way your adult dogs will not feel territorial.

Ditto on the neutral location!
Once you have a pack (3 or more) you may very well be in control of the pack as a whole but who likes who is out of your hands and the 3rd member could be an outcast even if it's tolerated by the other two.
Could you watch an old favorite be ignored at best, harrased at the worst?

Ditto neutral territory. Don't make the first introduction in your current dogs' yard. Take them all somewhere else-- park, vacant lot down the street and make very calm, controlled, non-threatening introductions there. And then follow the rest of everyone else's good advice above.

This is doable. I have four. Many people on this board have as many or more. But harmony doesn't just happen. You will need to establish and strictly enforce a zero tolerance policy against any displays of dominance or agression from day one. There is no "let them work it out on their own."

Eta: 6 weeks is too young to bring any pup home IMO, unless the situation he's coming from is a bad one where he's being neglected or worse. 8 weeks is better; 10 is better still.