"Hiking and Backpacking in Swedish Lappland" is an excellent article by Lars Bergquist.

The big hiking organisations of Sweden and Norway have homepages:
Svenska Turistföreningen and Den Norske Turistförening.

An excellent private server is "Utsidan" for Sweden and "The Willassen Guide" for Norway (in English)

The "Nature Conservation Board" provides information about the National Parks.

In Dutch language:
Aktieve vakanties in Zweden, by Henk Kersten

Accomodations for backpackers are collected in: www.BackpackingEurope.com