I can see a number of ways to achieve this. First of all what language to you code your pages in. (not the actual language but the programming language :) )
If you are using a scripting language you can set your pages up to display the same content but in different languages. One way if doing this is to have different language content read from a database. The preference can be set by the user.
Another way if doing this and one that may not be preferable is to have different mini sites for each language. For example if you have a site on French use www.example.com/fr/ for Spanish use www.example.com/es/ then have the correct regional content for each language. The problem with this situation is what to do on www.example.com perhaps just a link to each of the regional homepages.
I think simply put flags of available languages on my english page
Using flags is a bad idea when dealing with multi-language content. Flags represent countries, not languages. Which flag would you use for Engish? The Union Jack? The Stars and Stripes? Neither will work for me, as I'm Canadian. How about French? Again, I speak French but I'm not from France.
Using words rather than flags is a better option unless the different versions are really country-specific. English, franšais, dansk, suomi, Deutsch and not the English names too. :)
I agree with mack that the best way is to either language-specific subdirectories, or subdomains if each language variant is truly a separate site:
I was thinking which flag i would put for English lol and you are very right ill go with words :)
as for, example.com/de/
Then my content will be far from root 2 levels which i already have 3 levels and if i use /de/ everything in directory should be in German but i want to post news in English only.
I just think to say something like 'this page available in German, French' cause i will ask friends to translate them free so 1 page can be in French only but other page can be German and French .I know its not professional but i dont have money to pay for it :(
So may be better i use example.com/node21/german.html