Mountain Biking - 10 speed cranks with an 8 speed freewheel? help explain....

I'm in the market for a new crankset for the spring (k I'm lookn a lil early)
I was looking at a hussefelt 2.2 and perhaps a deore with a bashguard.
The problem I'm running into is they're listed as 10spd cranks or 2x10 (3x10 in the deore case) I'm running 8spd freewheel with xt RD. If I get one of these cranksets will they be useless without converting the rest to 10spd or can I safely run my 8spd setup withoUt failuure/error/not running properly?
I currremtly have a cheapo riveted sr suntour stock crank and would really like the extra clearance and durability a double with bash provides. Changinf bb doesn't matter to me cuz I have square taper ayways so I'd have to change it with the crankset in most cranks I've read about.
Bicycle in question a slightly customized 2011 norco mountaineer (hence the 8spd w xt)

Can, but won't be spot on perfect though...

higher speed crankset means the chainrings are stamped narrower to squeeze into the narrower chains. Your wider 8spd stuff will fit onto it just fine. Maybe take a slight durability hit since the rings are lighter.

the speed of the front derailer itself matters more; a wide 8spd chain will rub in more gears if you try to run it through a narrow caged 10spd front derailer.

Why not get a 9 speed Deore: http://www.chainreactioncycles.com/Models.aspx?ModelID=40496

As others have said, it will work. And as cobba is getting at, why not go with a 9sp? Those are still readily available and should work a little better and be more durable.

Go with the Deore as posted from Chain Reaction. Hella good deal.

Do those rings still come apart?

Yes.