Need some more help please
1.How often does he spawn because the way those rings get sold i can see him spawning every map!!
He spawns once in a game, meaning if you're working in Act 2, and see "diablo walks the earth", go to act 1, visit the Den of Evil, and UDiablo will be in Corpsefire's place. You can then ignore him and continue in act 2, or skin the lizard there and sift through his drops there, then go back to act 2 when you're done.
2.Both myself and my wife died against him then when we came back to get our bodies he was gone?
I play HardCore, so when I die that's the end of him. This won't work for you. Get your resists maxed (e.g. Rogue merc with Humility armor), get your resists caps boosted (Loyalty shield, Zod in your ammy), and get "Magic Damage Reduced By (some large number)". This attribute is cumulative if you have it on several items. "Damage reduced by" will help also. "Fire Absorb" and "Lightning Absorb" equipment will help.
That's "Surviving UDiablo"
Killing him is another question, and it's a job for Crushing Blow. Smite is an excellent method for delivering crushing blow, as is Strafe if you have a source of Concentration (Pally aura) around.
3.Is there a way to socket items besides the way you get in act 5 as a quest reward?I have read alot of people socket many items to boost their resist`s and was wondering about it.
There are a few items you can't socket: boots, gloves, certain UberUniques, and anything that already has a socket in it.
There are limits to how many sockets an item can get, which depend both on the item type and the item ilvl. There is a table somewhere... The socketing method is what DrowElf gave: nSocket*2(pGems) + item in cube, hit transmute, and you have an object with sockets. This makes PGems important, so grab a set of bags and start stuffing in gems.
Also grab up a set of caskets (same as Gem Bags, but are for brains, eyes, spleens, etc).
Also grab a set of Oil Barrels and start keeping the oils, especcially the ones you don't want. 25 of them make a Moderator doll, which can change ANY Normal item to Exceptional, and any Exceptional to Elite. You can have a Bartucs Breastplate turned into a Greak Hauberk so you can put 4 sockets in it (brestplate and cuirass can only take 3 sockets) and put 4 Um runes in the sockets for 60% resistance to all, 28% resistance to magic. (BTDT Standard Procedure).
5.At what level character do you start gambling the very best uniques and set items (im level 87 now)
The very best uniques cannot be gambled. You can see basically what they look like by downloading the "SP Cheat Items" package Joe put together, and then go get them for yourself by getting into Hell, killing Nihlathak, and going down below his "dungeon" to the levels that look like "Crystalline Passage", there you'll find that the "frozen river" has become "to a nasty place". Do this in Normal with your level 87 characters as a practice run, then in NM until you reach level 90. Then start adventuring through Hell.
In the 4 "nasty place"s (one per level of the dungeon that looks like Crystalline Passage) you will meet succubus-like vilewitches that can (rarely) drop unique charms that are soul stones that are a bit better than annihlus charms. You also can get an annihlus charm from UberDiablo in the A5 areas in Hell. (go through the Red Portals, one of them has UberDiablo behind it).