All of the worlds that I've created since the 1.7 release don't have jungle biomes (or at least non that I can find).
I spend hours searching for a jungle biome in a world and I can't find any. I search at the desert borders because it there were usually there before 1.7, but in the desert borders I only find Acasia Wood trees.
If there still are jungle biomes, where are they located. Which biome are they next to? Desert, Mountain, Ocean, Plains, Forests?
Jungle biomes as in the 2x2 large tress that grow? Yes they are still there
The locations for biomes have been better improved so you will not get a desert next to snow.
I have seen them around plains, forests and sometime just near a desert.
Keep looking, you soon will find them
Yes, just keep looking. I have seen forest next to deserts and forests before. Although they do generate in worlds, I have not came upon them quite as often. Biomes are also more randomly generated, so it's a bit harder to locate a specific biome. Also, you could try looking up seeds with jungles for 1.7.4, I'm sure there's some out there.