Don't take it to a shop, they will just send it to a repairer and probably add a mark up for the privelege.
try contacting one of these repairers directly:
Canon UK
Unit 130 Centennial Park
Centennial Avenue
Elstree Hill South
Borehamwood
Elstree
Hertfordshire
WD6 3SE
Tel: 0844 369 0100
Fax: 0844 892 0849
Web:
http://www.canon.co.uk
OR; any of the Canon service agents here;
A.J.Johnstone & Company Limited
395-399 Central Chambers
93 Hope Street
Glasgow
G2 6LD
Tel: 0141 221 2106
Fax: 0141 221 9166
Web:
http://www.ajjohnstone.co.uk
Colchester Camera Repair Services
6 Kings Court
Off Newcomen Way
Severalls Business Park
Colchester
CO4 9RA
Tel: 01206 843 322
Fax: 01206 843 323
Web:
http://www.camera-repair.co.uk
H. Lehmann Limited
247-249 London Road
Stoke-on-Trent
ST4 5AA
Tel: 01782 413 611
Fax: 01782 744 579
Web:
http://www.lehmannsdirect.co.uk
how bad is the cracked screen? does it mean you can't review images at all, or is it just irritating?. It might just be that that you've cracked a protctive screen that is quite easy and cheap to replace.