There have been mixed results on this. Undoubtedly there are very talented programmers in India who can work for a far lower salary than those in the West and so they offer far better value for money.
Unfortunately there are also conmen and fleecing you out of a few hundred dollars means alot to them but too little for you to start any kind of international legal action. You are also opening up your entire code (and security) to people in a very distant, and poorly regulated, location.
We do all our SEO work in house to maintain total control and security but we do know the following has happened:
There is also a very interesting article on smartlifeblog about one person's experience when outsourcing blog commenting to a company in India: http://smartlifeblog.com/experiment-outsourcing-my-blog-commenting-to-india/
"A few rotten apples" to be sure but certainly not all of India or Asia. However you will need to satisfy yourself beyond all doubt that you have found a reputable company. Or alternatively you can use us ;-).
I'm Tim Hill, a Search Engine Optimisation and Online Marketing specialist. I created this site to help others understand that SEO is not a mysterious black art!.
If your a newbie try the Getting Started in SEO page, otherwise feel free to dig around and learn more.