Hello there. I always hated the role of a jungler. Untill I tried jungle Alistar. And I loved him. Since then he's my number 1 champ for jungling. I'm going to point out some tips that could help you guys when jungling with the cow.
Runes I use (I can't afford another runes page) are AD/ArmPen/Armor/MagRes. Those are the ones I have. Not the best ones, though. Idealy you would run AtkSpd/MovSpd/Armor/MagRes. My masteries are 15/15/0 taking attack speed, magic penetration, ability power and bonus damage to minions in offensive tree and Smite mastery, armor, health regen, and damage return to minions. Why magic penetration? Alistars spells deal magic damage and his passive too, you actually want to deal as much damage as possible to creeps.
Summoner spells are smite and flash/ghost/teleport. If you take teleport you can ask someone to place a ward in a brush so you can invade their behinds... xD. If you take flash or ghost keep this in mind:
when you gank, the enemies will most likely burn flash. If they do you can leave them be and gank again soon because they burnt flash. Or you can flash too and Pulverize + Headbutt. If your spells are on CD then don't. You will be more effective the next time with both spells and flash available. The same thing for ghost.
Beforethe jungle changes, I would smite the big wraith, kill wolves and be level 2 and having smite up. Now you can take down the wraiths and then wolves and blue or go for wolves and then blue if you can get a leash.
One trick I noticed while jungling: when you aproach a creep camp hit the big creep and as soon you see their attack animation, use Pulverize. This way you will delay the creeps' autoattack timer and land 1 or 2 more basic attacks. This trick is really usefull at lower levels when you want to stay healthy.
When you reach level 2 (get Pulverize at level 1!) you can either take Headbutt if you plan to gank or Triumphant Roar if you want to keep jungling. If you take Trimphant Roar be sure to heal before assaulting a camp beacuse you won't have much time if you spot a gank. Also, when attacking a monster camp start with Pulverize and keep your eye one the Trample timer because you want to cast Roar as soon the timer goes off to keep Trample on.
At level 2 you should gank or go back to base and get Boots of Mobility (later in the game you can take some others but these will help you with ganking). When ganking, approach the enemy from behind so even if they do try to run away you can Headbutt them into a wall (because while they are in flight it's like they are stuned) and then Pulverize. Otherwise you want to make a W + Q combo. This one is tricky because it is hard to land it properly. Get into range first and then headbutt. As soon you see Alistar going cast Pulverize. If done properly it will act like a small Malphite ultimate.
Build: Get Sheen first after BoM. From here you can either build Trinity Force or Lich Bane. But! If you do not have enough money leave Sheen and upgrade it later. You want to get Frozen Heart and Banshees Veil. Then you can go for Randuins if they are AD based or FoN, Spirit Visage, Wit's End(?) if they are AP based. And don't forget Aegis of the Legion after Sheen. If you manage to get FoN or Trinity Fore/Lich bane early you can swap Boots of Mobilty for Mercs or Ionian Boots.
If you got some more qustions I will be glad to discuss them on the comments.