Template:Willkommen
Prepositions are tricky - I get them constantly wrong in English. Both phrases exist, "willkommen zu" and "willkommen bei". "Willkommen zu" is more formal, but less general: it can only be used for an event, never for place or a person, "willkommen bei" works all the time. So, never say "willkommen zu mir", if you have invited someone to your home, but "willkommen bei mir". OTOH, for a great event, you would prefer to say "willkommen zur Hochzeit unserer Tochter", though "willkommen bei der Hochzeit unserer Tochter" works, too - but doesn't sound perfectly right.
I just remember the phrase from a World Cup commercial in 2006, "Willkommen Zu Football"
Other than a few phrases and words ("arbeit macht frei," ich bin ein berliner," "schnel"-that last one came from a WWII story from my grandfather, apparently the Germans would say schnel a lot to pedestrians), I know no German. But I do know French and Spanish!
Sorry if my examples were a little too World War related. I'm certainly not anti-German you filthy schleu!
On another note, the reason most of the German words and phrases I know are WWII related would be that most of my family's accounts of Germans and most of what I learned of Germany in school was about WWII. I'm digging myself in an ethnic sensitivity hole, aren't I?
No surprise there: most British and American only know a few garbled phrases taken from Hogan's Heroes, sometimes not being correct German words altogether, like "Schweinhund". But I'm often surprised to meet Americans who speak some German - and these are often former soldiers who have been stationed in Germany.
OTOH, the only Russian phrase some Germans know is "dawai, dawai" ("schnell, schnell" - "fast, fast"): a relict of the many German prisoners of war who stayed in the USSR till the late fifties...
So it seems that wars are furthering the exchange of only a few words: let's see which Afghan expressions will come into the English language over the next couple of years...