One of my sites grew from 0 to 10.000 unique daily users (viewing about 30.000 content pages) within 3 years doing this:
The entrance page is created in the 3 languages of the web, auto-showing first the content in the http-accept language of the user if it fits to one of the web languages, if not, in English.
So if someone enters www.mysite.com or mysite.com he would get this, and robots normally logically get the English content first.
Inside the web is working with a frameset (navigation bars + content area/frame), each site shown up in the content-frame works even as an entrance-page (explaining the web, simple onside navigation etc.) if not shown in the frame-context and has links to the other language versions of this site.
Next I created sub-domains like [firstlanguage.mysite.com,...] [secondlanguage.mysite.com...] etc. pointing on the same physically directory on the server but showing up the content of the entrance page in one language only, so entering there a bot would get the content in the other languages too.
And finally I 'located' www.mysite.com and mysite.com by IP the zone-area of server's home country, and [english.mysite.com...] by IP in the zone-area of, for example, the USA and [suaheli.mysite.com...] by IP in the zone-area of, for example, the Swaziland …
The main search engines (like for example google) spider www.mysite.com and take notice of the existence of the rest, and with some special search requests they also show up results from the sub-domains, but normally all is going by the main domain.
Less important search engines spider all (if I admit it) like it were unique domains and show up all, but nobody uses this search engines.
The site is listed well in all main search engines, reality is, that users entering from search engines come per 92% from google, 5% from yahoo, 1% from msn, 1% from other search engines.
So seeing the site listed the same manner in all search engines maybe that yahoo is number 2 and msn is number 3 in the search engine listings, but looking up a the absolute numbers they're producing they don't have any importance yet.