Travel to Canada and back to USA on a multiple entry B2 visa

[pntakkar]

My parents have a 10 year multiple entry visitor (B2) visa for USA. They
are already in the US with a permission for 6 months.
There I94 is valid till July 15 2005. We plan to go to Canada by road for
couple of days on vacation on May 28 2005. They also got Canadian
single entry visa stamped valid till July 14 2005 from India. I have
following questions:

1) What is the procedure at the port of entry when we leave USa and again
when we renter by road?
2) Do we have to surrender I-94 when we leave USA and will we get a new
I-94 when we enter back to USA? or We will keep the same I-94 and be
allowed when we come back to USA?
3) Is there any problem for travel to canada for couple of days and come back?
4) Where can i get/Who can I contact to get official information on the
procedure for travel to canada and coming back to USA?

Thanks in advance

[immihelp]

I already answered this question when you sent an email in the morning.

1. Just show the passport.
2. No. Same I-94.
3. No.
4. It is really simple. It is just like paying toll at toll booth. Same type of line of cars. Just keep your passports handy, instead of coins for toll. And they let you go. That's it. Same thing while coming back.