This post will try to showcase an updated list of useful (and free!) training material available for Expression Blend:

Training Resources from Microsoft

Expression Blend and Design Blog: Tips & Tricks

Expression Community

Expression Blend (Online) User Guide

Expression Blend Tutorials

MIX 07/08 Video Sessions

Building Rich Client Experiences with Blend and WPF (by Celso Gomes and Christian Schormann)

Building Rich Web Experiences (by Celso Gomes)

Applications = Designers + Developers (by Celso Gomes and Kirupa Chinnathambi)

Designing Next Generation User Experiences (Johnathan Lansing)

Tutorials (Videos)

A Lap Around Microsoft Expression Blend (Steve White)

4 Visual State Manager Videos (Steve White)

Animation and Media (Peter Blois)

Blend for Programmers (Jesse Liberty)

contentpresenter.com - WPF Video Tutorials (Lee Brimelow)

Lynda.com - Video Tutorials 1, Video Tutorials 2 (Lee Brimelow)

Tutorials (Articles)

Nibbles Tutorials (Celso Gomes)

Collection of Visual State Manager (VSM) Resources (Steve White)

Electric Beach (Christian Schormann)

kirupa.com - Blend + WPF, Blend + Silverlight (Kirupa Chinnathambi)

 

If there is some useful resource you would like to see added to the list, please drop me an e-mail at kirupac[at]microsoft.com to let me know!

Cheers!
Kirupa :)