Google it. I'm sure you'll find many reads on it as it's a big topic.
From what I have read, the best way is to store pollen is in 35mm film cannisters and freeze it. I've read reports of it lasting as long as a year like this and 6 months is a definite possibility. Male pollen does have a shelf life though. It varies.
I'm not sure about plastic bags but if it were me I wouldn't chance it.
