they are completely different.
Perfect pitch- this is when you can determine the EXACT note when you hear a sound. larry carlton was able to pick the exact tone of a plane flying above.
perfect interval- this is extremely difficult to understand for beginners. an interval is a distance between 2 notes. it will take me forever to explain intervals but you can go to this site which explains it briefly
note: the word als.html was just when i ran out of space. it just continues the word intervals.
email me and tell me what you think