That is awesome! Congrats on the job interview. Here in the states it is not uncommon to start a job the next day after an interview for a few reasons.
One being, they have already done their research on you as an employee - contacted previous employers, verified references, etc before calling you in for an interview. This streamlines who they actually dedicate time to in person.
I am in the opposite position right now. I am transitioning from a full time job to working at home with my public relations company (writing press releases and video game manuals for a client). My day job is very accommodating about it - asking if I would be available to work "as needed" which I will be.
It makes working from home much easier as the hours they will need me there will cover my monthly living expenses (but not much else) while leaving me time to expand my PR company.
Enough about me. Lol. Again, congratulations on this interview. You will knock it out of the park.
Sounds like you've got a pretty good deal going on! I wish you lots of luck expanding your PR company :D
And thanks, I'll know more by the end of today I imagine. Usually companies here do some things after interviews, like for this job, they require some government info about criminal past (don't have one!) and such, but they can only ask for it once you're their prefered candidate I think.
Either way, I'll probably have to tell them to wait another week, because we need to buy a car.