Ken Roberts

web

Bikely has bike routes for places in Switzerland.

The national tourist website has links to useful info about bike routes.

Of course there are lots of resources for those who can read French or German or Italian.

English language

For reports about modern "recreational" riding in Switzerland, try englishforum.ch 

The archives of rec.bicycles.rides have some useful reports for the traditional "touring" style of riding.

maps

the Garmin City Navigator Europe NT digital map for GPS covers the roads of Switzerland, but I haven't tried it yet.

paper maps

There are regional bike maps around 1:50000 scale which are useful.

There are regional maps at other scales (not specifically designed for bicycling) which can be very useful for planning and navigating bicycle routes.

There's a countrywide bike map around 1:300000 scale which is useful for planning, but it gets tricky to use it for actually navigating when out riding.

guidebooks

We don't know any English-language guidebooks for bicycling in Switzerland.

Pretty much have to rely on trip reports on the web.