If you want to know everything about classic synthesizers, you should really check out http://www.vintagesynth.com/ before you look any further.
For over 15 years (since 1996) the Vintage Synth Explorer has been providing a fast and easy way to learn about vintage synthesizers.
They claim to be the world's leading synthesizer resource and have grown to include modern digital synthesizers, analog emulators, soft-synths, plug-ins, and other forms of electronic musical instruments.
On this site you will find detailed descriptions and reviews, pictures, audio and video samples, technical specifications, lists of famous users, links and more!
Very nice are also the site's Interactive Timeline of Synthesizer history, that shows a timeline together with synths ordered by production-date and their Glossary of synthesizer terms.
Like i said before, the site is updated very regularly, with both classic and hard-to-find synthesizer-gems; Check out the list with their latest additions for example:
EKO EKOsynth P15, Casio HT-3000, Waldorf Microwave - Revisited, Alesis Fusion, EMS Synthi Sequencer 256, Casio CT-401 and the MAM ADX1
Don't forget to follow them on Twitter (@vintage_synth) to keep track of the site's latest updates, and/or like them on Facebook