That's what I understand. You start off with a minimum set partition size, while the whole of the space you are going to use is made into the LVM setup and the partitions grow to the necssary size, using the un-allocated space as needed. The file system will also shrink down to the original size when files are removed. The original size is not supposed to be cut into. For instance, if you have a partition set as 3 GigaBytes to start, the smallest it will get is 3 GigBytes. But it could grow to however much you have un-allocated.
Before jumping into it , try reading these. They may shed some light for you.
The wikipedia articles have some words in blue. These are links to articles/definitions/other references. Follow them and then decide if you want to use LVM or a standard, set size partition scheme.
p.s. if you start in FC5 , no it is not necessary to have cd's to update. The major repositories are included in the necessary file configurations.