If you are going to go frost, you should pick up howling blast. It's great for either single or multimobs since it's AoE and it's ranged. You could use it with deathchill activated for a good opening pull on packs of mobs. Combine that with the glyphs for Howling Blast and Icy touch and you shouldn't have a problem keeping aggro or mowing down packs of mobs.

If you don't use howling blast, i suggest some form of

/castsequence icy touch, plague strike, pestilence, blood boil

it's good to have the pestilence in there before blood boil so your victims are infected with more diseases and generates more threat.

Others may have better macros they use.

This is my frosty tank. His talents need to be adjusted, but i have no trouble with aggro or damage as is:
http://www.wowarmory.com/character-s...doran&n=Tanakh