Steve at Square Wheels runs weekly rides on some great trails up around the Contin area. Square Wheels
There's the guys at Fyrish (gordymac etc) Fyrish Bikes who ride some of the best trails in the area and are seriously quick!
There was a club on the black isle too based around Learnie area. I think that the website was I think this is it but I'm not sure how active they are or if there's many organised rides. I've never been along to one of their rides.
That's the only ones I know of but there's bound to be more. I hope that you realise that you're moving to one of the best parts of the country for mountain biking (in my opinion of course!) with loads of natural stuff within 30mins drive, a pile of top notch trail centres and a fantastic climate.