I'll not debate whether or not Alba should win the role. I think she's pretty meh as an actress, altho I do think she's a lovely girl. But hey, talent is something you CAN gain and learn, so who knows? She may surprise us all.
What I did want to point out is that, contrary to popular belief, the idea of a Go-Gos biopic is BRILLIANT and DIRTY and AWESOME. Never a fan of their music, I happened to run across some faaaaaaantastic (and filthy) quotes from the band members in the book Rock Confidential: A Backstage Pass to the Outrageous World of Rock 'n' Roll by Coral Amende (2000).
"I had sex at the [defunt LA club] Masque; everybody had sex at the Masque. You just did. It was great. Everybody was making out with each other in the bathrooms -- lots of girls with girls. Everybody was on acid. My thing was acid or MDMA." --Belinda Carlisle
"We would freak our crews out, which is pretty amazing because you know how bad road crews are. We were so mean. We would spend hours trying to drive our road manager crazy. We would take pictures of our crotches and then slip them under his hotel room door and write, 'Guess whose is whose.'" --Jane Wiedlin
"We'd take naked pictures of each other in England in the woods, we were so bored. We looked like wood nymphs. We'd say to our road manager, 'We have naked pictures of us,' and he'd go, 'Yeah, right,' and we'd give them to him and he'd start shaking and then we'd snap them out of his hands." --Belinda Carlisle
"The most disgusting thing we got up to was the Corner Cleaners. Kathy started this thing where we would go into rest stops on the freeway and say, 'Let's be corner cleaners,' which involved getting into the corners and sucking up the filth with your mouth. It was always in dirty bathrooms with shit everywhere. Just repulsive." --Gina Schock
"This is how bad things got in 1984: Charlotte got thrown out of Ozzy Osbourne's dressing room. That pretty much sums up the height of our drug intake." --Gina Schock
"The whole thing was just out of control. I used to smoke angel dust, and I can't believe it now. There was a lot of drugs and a lot of drinking and a lot of puking." --Jane Wiedlin
Jane: Belinda, you were a major coke fiend.
Also, I'm trying (without luck) to find the video that they made backstage during their heyday of them making a few male groupies get dirty. I believe it was Gina and Belinda, and they were waaaaaaaasted. It was awesome. I saw it on Behind the Music, I think. If anyone can find the video, let me know, I'll add it.
Sources: Rock Confidential: A Backstage Pass to the Outrageous World of Rock 'n' Roll by Coral Amende (2000); my dirty memory.