It often works the other way. Your friend should start to get involved in meetups, and places locally that startups and entrepreneurial people congregate. Then it's possible he will be recognized for his energy, dedication, and be asked to join a funded start-up or create one with some like minded individuals.
That, or find some awesome online services that still have a handful of employees and try to apply. Y-Combinator is a place to look at startups that are already getting a lot of media attention, there are also some directories that list their startups But, he needs to get out there and stand out from the crowd. Startups are very particular about their first hires, and if he is working a boring 9-5 not building anything spectacular right now or making anything awesome they may not have confidence in him and it may be to risky.
There are so many places you can search for startups, though to find out more about each one you will need to do your own due diligence. Like what type of startup you are interested in i.e. App based, internet status, service base, domain specific like medical, mechanical, social media, food etc.
here, I am listing few places where you can visit daily, and get some idea what’s happening out there..apart from there..Google it!
http://500.co/ http://ycombinator.com/ http://techcrunch.com/ you can check the valuation and VC interests on - https://www.sharespost.com/ It provides you much more information on the particular startup and helps you to decide how much the change you are looking for is worth it.
To reiterate what ryan said about startups being particular about a first hire, we're going through that right now with a potential resources being pushed our way by an angel. We have a candidate who hasn't been in a startup before, and while he has very elite skills in certain domains, they're not the skills that soothe our pain right now. We don't have 'elite' work; we have our work - stuff that's just gotta get done, by the right hands.
My high school had a couple of really good sports teams, and the coaches would look to attract the best natural athletes as freshmen and then school them in the way of particular sport, producing All-Americans by their senior year. A startup can't take that approach, to nurture talent. A startup needs a player who skilled at a particular position in a particular sport. Sorry for the ham-handed athletic analogies, but for hires at the earliest positions in a startup, it's about getting the work done.
To meet entrepreneurs, there are plenty of meetups, boards like this one, as well as more universities are running entrepreneurial groups either directly via their alumni associations or can point out alumni-centric startup resources. They should contact their alumni affairs offices.