There is a really good graphics conference calendar system here that you can register with to receive updates and so on.

DiGRA 2007
September 2007 (Tokyo,Japan)
Submission Deadline: February 2007

Eurographics 2007
September 3-7 2007 (Prague, Czech Republic)

CyberGames 2007 International Conference on Games Research and Development
September 10-11 2007 (Manchester,UK)
Submission Deadline: May 14th 2007

Learning with Games Conference 2007
September 24-26 2007 (Sophia Antipolis,France)
Submission Deadline: May 31st 2007

ECGBL 2007: The European Conference on Games Based Learning
October 25-27 2007 (Paisley,Scotland)
Submission Deadline: May 17th 2007

Afrigraph 2007
October 29-31 2007 (Grahamstown, South Africa)
Submission Deadline: July 13th 2007

The Fourth Annual International Conference in Computer Game Design and Technology
November 15-16 2007 (Liverpool,UK)
Submission Deadline: September 29th 2007

FuturePlay 2007
November 15-17 2007 (Toronto,Canada)
Submission Deadline: June 30th 2007

December 1-4 2007 (Perth, Australia)
Submission Deadline: June 11th 2007

INTETAIN 2008: 2nd International Conference on Intelligent Technologies for Interactive Entertainment
January 8-10 2008 (Cancun, Mexico)
Submission Deadline: September 7th 2007

GRAPP 2008: Third International Conference on Computer Graphics Theory and Applications
January 22-25 2008 (Madeira, Portugal)
Submission Deadline: September 12th 2007

WSCG 2008: The 16th International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision
February 4-7 2008 (Czech Republic)
Submission Deadline: September 27th (Abstract Upload) October 16th (Paper Upload)

CGIM 2008 Tenth International Conference on Computer Graphics and Imaging
February 13-15 2008 (Innsbruck, Austria)
Submission Deadline: September 15th

i3D: ACM Symposium on Interactive 3D Graphics and Games
February 15-17 2008 (Redwood City, CA, USA)
Submission Deadline: October 22nd

Eurographics 2008
April 14-18 2008 (Crete, Greece)
Submission Deadline: September 21st (Abstract Upload), September 26th (Full Paper), November 30th (Short Papers, Education)

Computer Graphics International 2008
June 9-11 2008 (Istanbul, Turkey)
Submission Deadline: February 1st 2008

August 11th – August 15th 2008 (Los Angeles, USA)