Pepper has been a long time coming for us. We've been battling with Pickles for about a year now with personality "issues". I'd never call her a problem, but she was keeping us up at night. Scratching on our furniture, sitting outside our door crying incessently, and sitting on John batting at him as he slept. We hated having to put her upstairs at night, feeling like we'd ostrasized her from us. So after consulting many, many friends and our vet, the conclusion was Pickle was bored. She slept all day and wanted to play (with us) at night.
(sorry for the grainy pic. it's the only one I had)
The adjustment went really well. Much better than either of us thought. At first Pickle wasn't very excited about the new "addition". She shied away from her and if there was contact, there was a lot of hissing involved. Luckily, that only lasted about 2 days. Maggie could have cared less. She sniffed Pepper a bit and decided, "ok, another one". Pepper, having never met a dog, was very apprehensive of Maggie and would hiss (funniest thing I've ever seen is a baby kitty try and fluff up all big n' bad for a 70 lb. dog) and bat at her. After realizing Maggie could care less about her, they're all living peacefully.
again, sorry for the crap-tastic photo