Hi!
I think I have to write a bit about Siberian mountains.
There are some destinations for hikers: Altai mountains, Ergaki nature park, Karatosh river valley and East Sayan mountains near Baikal lake.

How to reach these places:
Gorny Altai - from Barnaul city
Ergaki and Karatosh valley - from Abakan city
Baikal - from Irkutsk city

Gorny Altai is well known destination with two main ridges for trekking: Katunsky ridge and North-CHuensis ridge. The highest point is Belukha mountain (4506m).
Ergaki ridge is compact and rocky with lakes and small rivers. Highest point is Zvezdny peak. There is mountaineering championship in july 2009.
Karatosh valley is little known area in the south of Khakassia republic.
Baikal is well known also. There are some ridges near Baikal with highest point Munku-Sardyk (3400m).

Web site with plenty photographs of these places:
www.siberiatrekking.com