I was looking for some sources of Science Citation Index impact factor, and I found the following two resources:
http://del.icio.us/giorgio.venturi/impact+factor
It seems that the most important journal in the HCI arena is Human-Computer Interaction, followed by:
- User Modeling And User-Adapted Interaction
- Interacting With Computers
- International Journal Of Human-Computer Studies
I also found a very interesting article on the evolution of the HCI field, based on the co-citation analysis.