Recent pollen collector myself. I included a couple of other links to different pollen collection methods as well. As for the When? question...Basically, you want to identify your male plant and let it start producing pollen sacs. Males will make tons of these. It's really not going to be releasing too much pollen until those sacs open, which they will do as the plant is starting to end it's cycle of life. All the instructional threads basically tell you to allow the male plant to produce a bunch of pollen sacs before cutting any branches off to collect. The more sacs it has, the more pollen you get. But if you notice lots of open pollen sacs, you're waiting a bit too long. You want to cut off the branch with the most pollen sacs and put it in the cup of water (or whatever method you want to use). From there. just keep the light schedule the same and forget about the plant for like a week. As the days go on, the pollen sacs will begin to open up and whatever method of collection your using will catch said pollen. I hope that answers most of your When question Merlin. The whole sac opening thing will vary plant to plant and may be dependant on conditions. As long as you see lots of closed sacs on your male, you're not too late so no worries. Just follow the directions in all of these links and you'll be fine. Best of luck. I think I saw you post a similar quesion in another related thread as well and remember that you already have a viable female ww or something right? If so, you may not necessarily need the male to make seeds. Their are ways of "tricking" the female plants into making seeds as well (feminized seeds actually) that you can explore if interested. Here is a link to one way of doing this in the event that it will help you
http://www.420source.com/post/82
https://www.rollitup.org/newbie-central/940-1-2-3-breeding.html
http://www.marijuanapassion.com/forum/archive/index.php/t-5958.html
http://www.420genetics.com/forum/growguide.php?do=viewgrowfaq&faq=38
https://www.rollitup.org/advanced-marijuana-cultivation/20319-seed-production-tutorial.html