Yet more proof of Paladin flexability. Just the other day I was asked if I could tank Magister's Terrace. I said that i was holy, but had some tank gear, but they invited me anyway. I've tanked before, even done a few heroics, and have realized that the Holy spec of a paladin is truly a jack-of-all-trades.
We made it through the second boss, but I had to go after our second try on him. In fact we could have had him on the first try if I had been more attentive. We had him down to 1%, and I was the only one left standing, soaking up his arcane blasts. If only I had hit my "Oh shizznizle" button (Lay on Hands) we could have had him down... ce la vie.
Since we're on the subject of paladin tanks. I've got a macro that might be helpful on grabbing aggro. A paladin has the ability known as Righteous Defense as of the release of TBC. What this does is pull aggro of at least 3 mobs off of a friendly target. This is all well and good, but if you're tanking a mob, you don't want to have to change your target to pull his aggro back to you. So, I've found this, which has been lying around for a while, that allows you to use your Righteous Defense as a Paladin taunt, much like warriors and druids use.
/cast [help] Righteous Defense; [target=targettarget] Righteous Defense
Though a Holy Paladin may be a jack-of-all-trades, he is still a master at Healing, which helped out during the boss fights I've done as the tank... it's nice when a tank can effectively heal himself (therefore generating even more aggro).