2-3 books/week isn't really speed reading, it's just making time for reading. Say that you have 3 hours/day that you can devote to reading. That's 21 hours/week. If you read a fairly average 60 pages/hour, a typical 300 page book will take 5 hours, and you'll be able to read 4 of them a week. At 100 pages/hour, you're at 3 hours for a book and will be able to read 7 (or cut your reading time down to an hour a day and still read 2-3/week).

It's much like programming though - you have to do it in big blocks or you won't get anything done. The first 15 minutes is just getting into the book, your mind wanders, and you don't get much out of it. It's once you've curled up for a half hour or more that you start really getting into it and can get decent reading speeds.