Antonio,

you do have the option of working on a contractual basis for design firms that develop special applications for other companies.

for instance, here in los angeles there is more work available than you can even begin to check out with independant, third-party vendors, that would contract you for a temporary "gig" (tarea). when the project is complete, you are done and have no further obligation. if you speak decent english (which i'm sure you do) and you have the skills, there may be no problem. there would literally be no way for the US governement to track you. then you move on to another contract gig.

the most difficult part about this whole thing would be getting here to california and finding a place to stay and having a VEHICLE. assume that unless you are in NYC, Chicago, Boston, or San Francisco, that you will certainly need decent transportation (a serious design flaw of the USA).

also, do not assume that competition is too tough in Silicon Valley. i go up there frequently and know that companies there are seeking people all the time. the only problem with Silicon Valley is that it is the most expensive place in the USA to live, with a bachelor apartment (smaller than madrid style) going for more than a $1000 a month. add car expense and it is sickening. the redeeming quality would be the high paying job you could get.

try the following for all types of info on computer jobs: http://www.computerjobs.com/ http://www.monster.com/ http://www.dice.com/
these sites will give you an idea of what types of pay rate you can ask for certain types of tech work. note the differences you can find in various locations of the USA.

good luck!!