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.

in gen 6 (x and y) you can easily "chain fish" and get a shiny pokemon fairly easily. it is not the same in BW2, unfortunately. you'll need to get the shiny charm by obtaining all the pokemon in the game (excluding the four event pokemon). then go to professor juniper and collect the shiny charm. this increases your odds from 1/8172 to 1/2724 i think. then, go into doubles grass and keep walking around. doubles grass basically has two opportunities to get pokemon in one battle, so the 1/2724 rule applies to both pokemon. that is really the only thing, other than the Masuda Method, that you can do to find wild or bred shinies.

there are a few in game shiny pokemon. beat Benga in the White Treehollow or Black City to obtain the shiny Gible or Dratini. I think if you breed with a shiny pokemon, it increases your odds of getting another one. But I am not sure about that.

also, if you just SEE all the pokemon in the game, you can talk to professor juniper and she'll give you the Permit, allowing access to the Nature Preserve, a special area in the game that can only be reached by plane in Mistralton. There, in the center of the Preserve, you'll find a shiny Level 60 Haxorus.

That is about it in BW2, I think. In other games there are more ways to get shiny pokemon, though. Unfortunately, if you do not have access to both Black and White Version 2, you cannot do this, as there are certain Pokemon like Vullaby and Rufflet that can only be found in their respective games.

I hope this helped!