Is here anyone using GZIP compression page to improve the web site speed? Will google / yahoo spider crawl such kind of pages correctly?
Google should have no problems displaying/caching a page compressed with Gzip. Infact I think they use it themselves (not sure of that though).
both, Googlebot and YahooSlurp will handle compressed content just fine. btw, you can see it your self in the webserver logs, the content size will be reported as compressed value there.
yep you can see from "see as google bot" in your webmaster tools that the Gzip is well read by googlw bot also other many info about the server