How long will it take after the visa interview to get my immigration visa?

[Andreas70]

Does anyone know how long will it take after the visa interview to get my family based immigration visa?

Can I expect to get my immigration Visa/Sticker in my passport the same day as the interview (assuming that the consular approves me for a visa) or will I have to wait a certain number of days/weeks/months before it is issued?

FYI: The interview will take place at the US Embassy in London (United Kingdom).

[Abhinavp]

I had my interview yday and the status today shows that my visa has been printed. I am expecting delivery by friday.
But if they put you in AP then it takes long long time.