Here's a note from the Air Traffic Control "bible"; FAAO 7110.65P

NOTE-
1. A descent clearance which specifies a crossing altitude authorizes
descent at pilot's discretion for that portion of the flight to which
the crossing altitude restriction applies.

This can be found here at this link;
http://www.faa.gov/ATpubs/ATC/Chp4/atc0405.html#4-5-7

You might also be interested in Example 4 under para 5-9-4. ARRIVAL
INSTRUCTIONS found at this link;
http://www.faa.gov/ATpubs/ATC/Chp5/atc0509.html#5-9-1

"Aircraft 4 is established on the final approach course beyond the
approach segments, 8 miles from Alpha at 6,000 feet. The MVA for this
area is 4,000 feet. "Eight miles from Alpha. Cross Alpha at or above
four thousand. Cleared I-L-S runway three six approach."
(See FIG 5-9-1.)"
The depicted situation is very similar to the first question posed
regarding the approach procedure.

JPH


Chris Brooks wrote:
By providing an approach clearance and a crossing restriction, the
controller has authorized you to descend to that altitude immediately,
and to maintain that altitude until you reach the fix where the altitude
restriction applies.


Again, excellent reply... thank you for your help. Do you know where the
above is written? ATC handbook I am assuming, but what part?

Thanks again.