Is there a method of finding Shiny Pokemon as of Gen. 5?

In Fifth gen there's a key item called Shiny Charm, that increases the chance of encountering a Shiny Pokémon, both in the wild and through breeding.
You can receive that item from Professor Juniper after obtaining all the Pokémon in the National Pokédex, with the exception of event Pokémon. But it's only present in Pokémon Black 2 and White 2.

I don't think there's something similar in Pokemon White.

Note: As a key item it can't be traded from B2W2 to any other game.

In Pokemon Black and White only (not Black/White 2), you won't have access to the Shiny Charm, nor is there a PokeRadar as there is in a few other generations, meaning 'chaining' Pokemon is a lot harder if not near impossible. Thus the most reliable method available to you to increase your chances of a Shiny Pokemon is the Masuda Method:

What is it?

Named after Game Freak director Junichi Masuda who programmed it into the game, the Masuda method is a fan-made term which describes a breeding technique using Pokemon from different language-regions, that results in higher chances of hatching a shiny Pokemon. While the standard encounter rate for a Shiny Pokémon (either in the wild or by breeding) is 1/8192, the Masuda method multiplies this rate by 6 in Generation V, to 3/4096 or about 1/1365

How does it work?

Say you have a Pokemon from a foreign region that you breed with a Pokemon from a different region (either your own region, or another foreign one). For example, a Butterfree from the French region bred with a Butterfree from the US region. Or a Lapras from Japan bred with a German Feraligatr. So long as the regions differ, the extra chances at a shiny will be applied.