VB.NET parse datetime string to get just time

Assistance getting a value out of a datetime string using VB.NET,

We start with a string for the startTime = 1/8/2009 5:30:00 AM

How do I  parse this string to get the hour of the time (i.e. 5)
then, parse the string to get the minutes (i.e. 30)
then, parse the string to get the AM/PM part

and then convert it based on,
 
if the minutes = 00, set the newStartTime = 5.0
if the minutes = 30 set the newStartTime = 5.5
if the AM/PM were PM, then add 12 to hours so that newStartTime = 17.5

I am new to computer programming, and have been trying to learn via books and online videos.

Thanks,
Joe