I've given up on software companies producing manuals for about the last 10 years - If you are lucky, you get a pdf file of a manual, but usually its just a 'quick start guide' as with Lightroom, which as you say is not that good, although it does give you the basic workflow of the program.
Lightroom and Photoshop CS3 are two differnt programs, although there is a lot of overlap between them.
I tend to use LR as an image database, raw image adjustment program and raw converter.
I use Photoshop (CS2) for any other PP work not covered by LR and also use CS2 for cropping/re-sizing, although you can do this in LR I prefer to use CS2.
There are a lot of third party books out there, and the best ones will have sample exercises to give you a better understanding of the program(s).
You won't learn either of these programs in a day, especially Photoshop, but after a time you will get the hang of them. There is a learning curve and for something like CS3 its pretty steep
