Well the title kinda explains what i want to know right ? :P
What i want to know is your taughts about my gear, what I should improve, is there any sockets or enchants i should replace, change my talent specc or something similar to that. Also i want to know if you think I'm ready for off tanking or even main tanking in Ulduar 10 man.
Your spec is fine and it looks like your gear is definitely able to tank Ulduar 10 man.
I would suggest getting the PvP shoulder enchant (30 stam, 15 resil) until you've got Sons of Hodir rep. It costs 10k honor and only takes a few BG's or Wintergrasp battles to get. You can buy it at the accessories vendor in Stormwind from memory. It would also allow you to lower your defense to 536 and remain crit immune, so you could swap the gem in your belt with a stamina gem as an example.
If you also want a bit more health you could swap your dodge trinket with the Essense of Gossamar (available from Heroic: Azjol-Nerub second boss).
All in all your gear will be fine in Ulduar 10 man.