I am going to move this to the "Jobs" forum.
The key thing are "references". They make a world of difference. You can work on sourceforge projects, but you won't get any references. You can work on them for your own knowledge and to build up a portfolio of projects to describe during interviews. But also make sure you get a couple of people that can vouch for you and say how good you are. This is where interships come in. So they are absolutely essential. Unless you go to a great university or are at the absolute top of the class, without experience, you probably will have trouble finding a job at first.