***EDIT *** This is only valid for the old debian image that dont have hardware floating point support. For newer images (rasbian) you have to compiöe from source.
It is realy simple to install a Tellstick on the Raspberry PI. For the one that is interested the following will install everything you need on a clean debian from the Raspberry PI downloads section.
sudo apt-get install libftdi1
Add the following line to your /etc/apt/sources.list:
deb http://download.telldus.com/debian/ stable main
sudo apt-key add telldus-public.key
sudo apt-get update
sudo apt-get install telldus-core
There have been a couple of questions/request to include weather data (temperature) from online sources like yr.no or temperatur.nu, yesterday I did an implementation of integration towards temperatur.nu but I have some concerns about their (and yr.no) terms of usage. I.e. they require that there logo/link is displayed next to values from them and that would be very hard to fulfill if I integrate it so that it is a variable that is updated. However I just want to let you know that I am working on this and I hope I will be able to present a solution that is acceptable with regards to the weather services terms of usage.