First thing i can say is
If a game loads in 30 seconds using the normal way, would the time half to 15 if I used RAID? Same for programs?.
No. It'll get the data from the disk to the processor faster but then it depends on how fast your processor and RAM is.
RAID 0 is used to make 2 HDDs appear as one big one as far as i know. Its not really even a proper RAID Array (RAID stands for Redundant Array of Independant (or Inexpensive) Drives) As RAID 0 offers no redundancy it.
RAID 1 onwards are true RAID arrays but have their pit falls. They fall into two types Mirrored and Striped.... click here
If you just want games / programs to launch faster then get more RAM. Otherwise more info on what the PC is used for will give someone a chance to help you further.