According to me the number of study hours required varies from person to person, still i personally feel that if you can spend most of your time for studying for SCJP you would need around 2 to 3 months based on your personal ability.
I suggest you study core java first before you opt for studying for SCJP.
Khalid book is one of the best ones ( according to the reviews which i have read ).You can visit my site SUN JAVA 4 U
for more resources.
you can mail me at email@example.com
, if you want any other specific informations.