Let me start with morph first, it's easier. Morph is an ability that has a "built-in" text. ANy card that has "Morph" and a cost written in it can be played for 3 as a 2/2 colorless creature with no name and no ability. The card is played on the table face-down. Because of this, whenever a face-down card would leave play for ANY reason (even if it was going to be returned to its owner's hand by a card HE played) he has to reveal it, because if it was a card WITHOUT morph (and believe me, I've seen my share of players playing face-down basic lands in tournaments), it's considered cheating. Once the card is played face-down, you can turn it face up by paying its morph cost at ANY time you receive priority. This is NOT an activated ability, it's a special action that doesn't even use the stack, so, for instance, you could turn a Willbender face-up and redirect an Extirpate aimed at you, even though Extirpate has split second. When a morph card is turned face up, if it's a creature (there are cards like Zoetic Cavern, for example), it's not considered as a new object, so if I chucked a Terror at your Exalted Angel while it was face-down, turning it face-up won't save it from the Terror (contrary, for instance, to playing Momentary Blink, which would make it a New Object, thus making Terror lose its target). Auras and equipments attached to it remain attached to it, unless it's impossible (for instance, the creature is enchanted by a Moldervine Cloak and, once turned face-up, has protection from green). I guess this about covers it.
As for planeswalkers, I already answered about it, which you can find
here.
If you have further questions, please feel free to keep asking, I'll try to answer them as best as I can. And if you need any clarifications, also, go ahead and ask. Hope I could help.