There are several proposed mechanisms to "enable" SPDY. The preferred is to run over SSL, and to use their NPN extension to negotiate SPDY support: http://tools.ietf.org/html/draft-agl-tls-nextprotoneg-00.htm...

Alternatively, there is work on sending an "upgrade" header in your regular HTTP response: http://code.google.com/p/chromium/issues/detail?id=69688

The NPN route is obviously the best in terms of performance, since the protocol can be negotiated as part of the TLS handshake..

Long story short: you can definitely run your own SPDY server and Chrome will auto-detect and use the protocol.

Yes, its all open, and there are non-google SPDY servers out there already. My own site (you can probably find it) will speak SPDY for you.

If you have any trouble, please hop on to the spdy-dev@google.com mailing list for help.

The last bit of the article tells you how you can implement SPDY on Apache with either Ruby or Python.

It looks like SPDY-enabled clients check for SPDY implentations first (which fails very quickly if absent) and then fails over to HTTP.