About life in Chile, visa processes, doing business in Chile, and the general cost of living.. well, you can find information here: http://startupchile.wordpress.com/destination-chile/

In terms of salaries for a developer with at least 2 years of experience:

Program Analyst: $1210/mo Informations: $1450/mo Civil Engineer, Information: $1700/mo Programming: $1100/mo Design and Industrial Production: $700/mo

Are there other foreigner software startups / companys or immigrants ?

There are companies such as Wanako Games (NYC), Bio Architecture Lab (Berkeley), Bling Nation (Palo Alto), Atakama Labs (SF), Entegris (Nasdaq: ENTG), InquiroGroup (Palo Alto) and Zappedy (SF). More information on http://supercoolschool.typepad.com/startupschool/2010/08/sta...

What about the English skills ? I think you will be fine here, there is no deal if your software is written in a different language. (I'm not sure if I understand your point with the english skills.. you're worried because you have to learn spanish?)

Hope it helps, any doubt, don't hesitate to ask.