Is it necessary? or will normal runes for your AD champs be fine? if you do need it what would rune page for jungle need to b?

most jungers should go with armor runes, some wont need them taugh, xin for example

With the new changes to the Masteries, and with Dodge being removed from the game there is no real need to make a rune page for Jungling, on Twisted Treeline or Summoner's Rift. Now you can get away with the masteries in Defense that reduce the damage taken by minions, and Bladed Armor.

To be honest though, I use offensive Masteries, and AD runes for jungling, and it works great.

depends on who your jungling on.
for Shy/Cho i use AS/armor and 0/21/9
for olaf i use Armor/Mresist/Apen 0/21/9
for udyr/Noct Armor/apen/AD 21/0/9
for caster jungle i do mpen/mp5/armor/flat ap 9/9/12
Alot of it comes down to personal play style tho and how you do things
they are pretty clearly labeled for the runes in my summoner profile if you have ?'s hit me up

like svarok said just depends on the jungler

some like pure armor pen
some like pure attack speed
some like attack damage with pen
some have a mixture

but all of the junglers imo should have armor yellows

I don't really use 'jungle' runes when jungling in Twisted Treeline. I stick with my usual Armor Penetration marks, Armor Penetration quintessences, Armor seals, Magic Resist glyphs. I also use offensive/utility masteries. 21/0/9 usually does the trick for me.

I jungle in Twisted Treeline as Udyr, Lee Sin (the best in my opinion), and Nocturne. All benefit well from those setups, and all have some sort of self-healing ability that is useful in the jungle.

Jungle Runes :
Red : Armor Pen., AttackSpeed(Cho, Fizz)
Yellow : Armor ( A Must )
Blue ( Attack Speed ), Don't need MR, unless full team is AP, but probably never going to happen.
Quints : Attack DMG for a quicker jungle. Even if it scales off late game. Still wonderful for beginning/middle game .