The basic frost spec looks like this:
http://talent.mmo-champion.com/?deat...0&version=9757 . You can move the 2 points in Epidemic to other talents like 2H spec or any utility you want.
Your rotations as frost spec depend on whether you chose to take the glyph or Howling Blast. Without the glyph, on single target you'd do something like IT-PS-(Deathchill)OB-BS-BS-(Blood Tap)BS-(RP dump with FS) -OB-OB-OB... The most important thing with frost spec is to keep FF up at all times and be watchful for Killing Machine and Rime procs, use Frost Strike for KM procs, and HB for Rime procs.
For any spec, you should macro Rune Strike into all your abilities, it will give you a huge chunk of threat. And use your RP dumps only when you have more than 50ish RP, to ensure you always have enough RP for RS.
I wouldn't really say any of the trees is considerably easier or harder. IMO you should chose your tree depending on which play-style you like the most, and maybe on which buff you want to bring to your raid.
Edit: This EJ thread has very good info on the differences between the 3 trees for tanking:
Suno's Fireside Chat - DK Endgame Tanking (Updated) - Elitist Jerks