Wanted Decent Bike

Lads,
Decided a few weeks ago that myself and the bro are going to do a bit of mountain biking this year...thinking of hitting forest trails for a start to get us into the zone...2 x six plus footers, (1 overweight!)..talking to a friend he said we need decent bikes..suspension, hydraulic brakes etc..a few questions remain in my mind...what size of bike do we need? what's the story with pedals? I have click on boots for my racer..(are they any good on the mountain) and thirdly where should I start looking to buy a bike..?
Any help appreciated
Well now, if this is going to stick you are in for a wild old time.
Starting off, heres a few tips.

Hardtail - thats just forks on the front - Rockshox Recons 100mm
20" Frame i'd say maybe 19" go to a real Bikeshop where real riders work and I mean real riders, thats people who have ridden/ride all manner of bikes and get fitted.
There are a ton of good bikes, spend no more than €1000 starting off, in fact you should be able to get something decent new from about €650 but probably wont have Recons or similiar.
But you'll get away for a while with own brand forks and they should have reasonable starter disc brakes.

Get good advice though, essential. I am biased about Eurocycles brands, Felt, Corratec and Focus but there are other good brands out there Giant, Specialized, Cannondale, LaPierre.

Get spds straight away and proper shoes, start off on them , you will get used to them very quickly,
Flats are for pro DHers and BMXers. If you are going to ride on spins, then use SPDs. You should consider them the same as Fins for diving or Bindings for skiing.
You're in Tipperary , I would go and visit Chris O Callaghan in Ballyhoura Trailriders. I would not recommend anybody else down that direction.
http://www.trailriders.ie/

there are loads of people who will spout tons of crap at you about whats good and whats not but I know best.
a 20" Hardtail
Rocksox Recons 100mm
Shimano Drivetrain
Shimano discs

This is the best setup for beginner MTBing..the above bits are reliable, sturdy and spares are easily available, give yourself a few weeks before you start fretting about the best tyres, helmets and all the other stuff people waffle on about on the internet forums !

go and see Chris, hire a bike , talk to him about whats the best way to proceed and tell him Richie Byrne sent you.
Don't get sucked into the Tyre/Flat pedal, baggies/lycra load of me bollix. Talk to a local expert, get some instruction and above all go and enjoy yourself.
Richie
Ta Bryner

Thanks for that - I'll hit for Bally and see what story is - at least I have the basics clear..A 20 inch hardtail...I just went to Bally website and maybe the best thing is to spin down and give a day on a rented bike and see what story is - i'll touch base with Chris..
they are clipless pedals, same idea as bindings on skis. I've been teaching people mountainbiking for 20 years and in my opinion its best to accept these straight away and get used to them before the usual nonsense of flats v clipless starts, as that is a 99% religion rather than a physical argument.
talk to Chris, its way easier to demonstrate the practicality of them in the flesh rather than describing them and how they function.