**UPDATED JAN 16 WITH NEW PATCH**
Taking double golems at level 1, if uninterrupted by the enemy, is pretty much a free botlane win for blue side, as you'll hit level 2 long before your enemies will and so will be able to start zoning almost immediately upon arrival to lane. For the most part, I think it's actually better to let the support kill the big golem, but it depends on the lane---whichever champion has the biggest power increase by leveling to 2 is the one who should take the big golem, as the advantage you can get in lane from having the extra level is worth a lot more than the worth a single golem kill.
As a lot of people have figured out already, double golems can actually be *easier* in preseason 3 for the carry-support botlane to take at level 1 without taking any damage. Here's my favorite way to do it with a ranged support and ADC:
Have the ADC stand to the left of the small one, the support to the right of the big one. When the golems spawn, the ADC pulls the small one while the support pulls the big one. The support should damage the small one either with an autoattack or with a spell and an autoattack so that the ADC can kill it faster and then kite the big one by walking right to the edge of its leash range and then slightly further, then as it almost resets, walk back towards it and autoattack so that it reaggros, and repeat. The ADC can just tank and kill the small one and then turn towards the big one to kill it; now you kite the big one as you used to in the old season.
With melee supports, you can do somewhat the same thing, but it's much harder to pull off correctly, and I recommend practicing it several times before trying it in a real game. The support should stand near the big golem off to the side while the ADC pulls the small one. Now the ADC kills the small one in the same manner as if the support were ranged, while the support kites the big one around the reset point---the reset point is marked on the terrain with a small mushroom, so you walk just past that mushroom and then turn around to reaggro; you should be able to keep it within a very small distance to you this whole time.
Actually killing the big golem is somewhat harder: You kite it back and forth the same way as you did under the old jungle. However, since ADCs are likely to not be opening boots, it's pretty much impossible to do without tanking it for a little while. If you're Leona, Taric, or Alistar, apply your CC to the big golem one time. If you're Nunu, either your W or E will allow your ADC to kite the golem. If you're Blitz, it's gonna suck, and you'll almost certainly need to use a potion at the end. This is fine though, because Blitz should be invading anyway.
And how can Riot fix this ridiculous imbalance in blue vs purple side? Have double golems spawn at 1:54 instead of 1:40.