Press passes, generally, are given out to those in accredited media outlets (major papers, broadcasters, etc.). However, this shouldn’t stop you from interviewing people.
Generally if you’ve got a story accepted (be it a magazine or school paper), you’ll find people are fairly willing to speak with you.
Of course, the higher the profile the person has, the harder it is to get an interview. This is usually because they’ve got media handlers or PR people to manage the time.
So, if you wanted to interview Alexei Yagudin, for example, you’d probably first need to talk to his manager and arrange time, as well as explain why you want to talk to him (e.g., because you writing a profile).
As for media scrums, by their nature they are somewhat chaotic. This has an advantage in that the subject of the scrum won’t realize you don’t have a “press pass.” However, because it is a scrum, it’s tougher to get past the beat reports and to ask your question.
Before starting any interview, though, it’s incredibly important to do your homework. Know what questions your going to ask, and know the background behind those questions.
The real trick is speaking to the right people so the interview can actually happen.