Off the top of my head, why not try the following?

In Winkel, just out of the city:

http://www.tierrettung.ch


Tierheim Winkel (near the Zürich airport)

http://www.tierambulanz-verein.ch/Gassigehen.htm


Near-ish Bhf Oerlikon:

http://www.tierheim-surber.ch/


A good group in Valais needing help, just in case you find your way there sometime:

http://www.lvpa.ch/refuge/refuge.htm

In the Basel area:

http://www.tierschutzbund.ch/assets/...schutzbund.ch/


A Swiss group helping dogs in Italy:

http://www.tierhilfe-italien.ch/Home.htm


Other rescue group helping dogs here and from other countries:

http://www.sos-strassenhunde.ch/

http://www.hundehilfe.ch/phpwcms/index.php?home

http://www.tierschutzbund-innerschwe...rmittlung.html

http://www.tiere-in-spanien.de/

http://www.tierschutzengel.de


And, a few groups close to my own heart:

http://collies-suchen-ein-zuhause.de/

http://www.sheltie-in-not.de

http://www.collie-in-not.de/

http://sos-colley.forumactif.com/


Also, to find other Tierheim in your area take a look at :

http://www.tierschutz.ch

This is the national homeless animal database. You can do a search by canton, and under the individual animal listing click on 'Anbieter' to find the contact details of shelters - just give one near you a call and offer to help.

Edited to add:

http://www.oasis-des-veterans.com/index2.html

This is a group primarily in the French-speaking part of Switzerland who specialize in helping older dogs - they also work with rescues in France and Italy.

Good luck in your search...