It varies a lot. For the most part, if you can do those 3-D magic eye pictures halfway decent, it'll help a lot.
The seminars are taught in a weekend, if that's any gauge.
The general consensus is the book alone is okay, the whole system is better, and the seminar is the best, as far as ability to learn the system goes.
We have people on the forum who have spent a very long time trying to get Photoreading to work, and others who have gotten it very quickly with just the book. Some haven't been able to learn it even with the seminar, some have gotten the tapes to work in less than a week.
I can only say that, for the most part, if you're looking to be able to spontaneously activate like Pete does in the infomercial, it'll take quite awhile, and some people, even some of the best of the guys on this forum, still can't do it.
If it's any help, I got the tapes to work in about a week (that's the one in the infomercial), and though I've had instances of spontaneous activation, I haven't been able to get it solid yet.
Also, you should know that activating the book is the bulk of the system, and that it takes about 1/3rd of the time you would normally spend reading the book. So if a book normally would take you 10 hours, with the system it should take about 3 hours. I'm telling you this in case you have the impression it'll take you 5 minutes, which it won't, at least not for awhile.
Hope that helps.
-Ramon http://razor.ramon.com
PS - I am incredibly happy with the system, and it's one of the most useful things I've ever learned, if you want a testimony, drop me an e-mail.