If your current employer has offices in the US, you can try for a transfer. That's usually the best route in.
The US has a remarkably high immigration rate (2 million people a year, though not all of them are legal). Most of that comes from being sponsored by a close family member. We already have so many immigrants who still have close family (mothers and fathers, children, siblings) overseas, and are willing to go through the long process of sponsoring them, that we already have a heavy flow of people coming in all the time. Add a high unemployment rate and the outsourcing of technical jobs overseas, and it becomes nearly impossible to get in.
An employer must, first of all, be able to provide evidence that there are no Americans to fill the job. If that is so, which is unlikely, the employer not only has to be willing to sponsor you, but must spend money to do so, wait a long time for you to show up and start working.
If you had some skills in a specialty language or something, you might have a better chance, but internet designers are pretty thick on the ground here.
Consider Australia, where you qualify on a point system for immigration, and you don't have to have a job to move there. Look at the Australia forum stickies for information.