Formalities for starting a job with a family reunion national visa

Hi,

After a wait for nearly 4 months, I have been granted family reunion national Visa (spouse) recently. During the wait time I have been offered a job by a company in Germany and they are waiting for me to join them as soon as possible.
I want to know if I can join the job immediately after I arrive in Germany or are there any other formalities apart from registering at the local authorities, that I have to follow?

I have read somewhere that a residence title is needed. What is it and how long does it take to get it?

Thanks in advance.

After arrival, you need to (in this order)
- register at the local town hall or Bürgerbüro
- visit the local Ausländeramt and apply for a residence permit
- with the residence permit, apply for a work permit at the local Arbeitsamt
This process took my wife three months (and costed a lot of nerves - nothing is ever easy with German buerocrats!). How long it will take you depends on how busy your local authorities are - big cities in Western Germany (and Berlin) are slow, small towns and Eastern Germany faster.