Oasis'Definitely Maybe, their debut, helped jump start the period. Watch and listen, hear from the people that were there, get their thoughts, and then keep following the progression, and regression, as things build up, just to break down.
If you're interested in the Brit-pop story of the early to mid-90s, you're a fan of Brit-pop, or just want to hear a story. A universal story that could, at one time or another, describe any "trend" in music, than Live Forever is a good film to indulge in. Even if you're not interested in Brit-pop, the story line, hype, and eventual throwaway tendencies of the U.S. are explored here and make it quite interesting, at the very least. I'll give it a B+.