you can take a look at wwwdotarchivedotorg put in your site and it will show a range of dates when it was able to mirror your site.
use Internet Archive WayBack Machine tool of http://www.archive.org/web/web.php and see archives of your website..... it will surely give you good result.
go to www.archive.org, add your url in the top bar - this will show Google's cached history of your site
No, This will not shows google's cached history but archive.org have it's own crawlers "Heritrix" & "ia_archiver" for that and it shows it's own cache history
To find out when Google cached your site for the first time, click the link below, and replace yoursite.com with your website address. http://www.google.com/search?hl=en&q=yoursite.com&as_qdr=y9&btnG=Search EDIT: will not go back past 9 years. Cheers James