I totally agree with Wyrmrest. Every tank should get them to revered asap. You should be close to honored just through finishing dragonblight, and the cloak you get for that is great. Then the revered grind through dailies and some 80 dungeons is pretty worth it for the chest you'll get.
I wouldn't suggest tanking heroics until you're at the heroic defense cap of 535 though. Just my opinion, but recommending only 490 is pretty low, and if your dps isn't up to snuff, you're going to wipe a lot. There are enough crafted and blue 80 dungeon (as well as world quest!) rewards out there that getting to the cap is quite reasonable. Pick up the saronite tanking set from a blacksmith, it's pretty cheap and will help a LOT. You really shouldn't have any greens if you're tanking heroics, but, again, that's just my opinion and not a rule.
I'm sure this depends on the instance though, H UK might be doable, but something like Gundrak is going to be quite challenging--especially if the DPS is as undergeared as the tank.
But if your group is successful, by all means go for it.
(Also, if you're recommending the Red Sword of Courage--it's in H UP, not UK. There is actually a pretty awesome tanking weapon you can get from the Zul Drak zone for doing a really quick 3 man quest.
http://www.wowhead.com/?quest=12857 Either the hammer or axe are awesome until you can find something better in a heroic, or the eternally folded blade.)
Edit: From looking at op's gear, looks like he already did Ragemane and picked the sword instead of the axe or hammer, oh well. =)
Anyway, go to this page and it will tell you everything you need to know to get started on heroics:
http://www.tanklikeagirl.com/2008/12/02/wotlk-shopping-list-for-prot-warriors
Edit 2:
I'm pretty sure in order to DE wotlk stuff, you need to be 325 in enchanting--which requires getting level 50 and to outlands for the trainer.