White Balance Bracketing in NIkon D5000?

I have Nikon D5000. I can't figure out the difference between W1, W2 and W3 in WB bracketing. Have read the manual too. Can somebody help me?

I can only guess myself right now as i don't have any manual at hand and don't use WB bracketing myself:
It may decide how big the brackets are, just like the f-stops in case of exposure bracketing. Just try them out and compare the results.

To be honest, i don't see much of a point to WB bracketing though. If one is serious enough about it that one cares to get the perfect white balance, then one should shoot RAW and set the WB in post processing, e.g. Lightroom.

That seems like a lot of effort.

What we pros do is use a custom white balance tool like the Xrite Colorchecker Passport. With it, you can batch process each shooting session under similar lighting using it and Adobe Lightroom

The cool thing about it is that you can use different camera bodies and have all their white balances match.

Here is how that works:

http://www.xritephoto.com/ph_learning.aspx?action=webinarsarchive&eventid=940&eventdateid=4709

Now I can white balance 300 or more photos shot under the same lighting conditions in just a few minutes. Accurate colour is very important when shooting textiles, especially when shooting fashion