Attiny question

Im new to Arduino and am looking at using an Attiny microcontroller. Is there any differance in using the http://search.digikey.com/us/en/products/ATTINY45-20PU/ATTINY45-20PU-ND/735465 or the http://search.digikey.com/us/en/products/ATTINY45V-10PU/ATTINY45V-10PU-ND/735467 I want to use the Attiny45 10pu because it is able to operate at 1.8 volt. Could I program it the same way the MIT high low tech group programmed Attiny 45 20pu?

Yes.

ATTINY45-20PU is a 20MHZ max clock ATTINY45V-10PU is a 10Mhz max clock