Can files be exchanged between FAT32 and HFS+ partitioned drive? I just got a LaCie 1TB external hard drive and I have a MacBook Air with OS X 10.8.  I often exchange movie and music files with friends that have PCs.  


If I were to partition my drive to have 250 GB formatted to FAT32, and 750 GB formatted to HFS+  to be able to exchange files with friends, can I also move files back and forth from the formatted FAT32 portion of my hard drive to the HFS+ portion of my hard drive?  
And if I can do that, would the file exchange from the differently
formatted partitions 


have to be done on a PC, 
or could I do it on my Mac?  

Also, is the HFS+ system compatible with the old school Mac
books?  


I am not tech savvy, so I apologize for the verbose, non technical wording.
It might make sense to make the entire drive FAT32 to ensure readability between systems, unless there is a need for having multiple partitions not described in your question. As for the specific answers,


Yes, dependent on #2
The files MUST be moved on a Mac because a PC cannot read an HFS+ partition by default and even then, cannot read without special software. Your friends would only be able to read the FAT32 portion of the drive.
Yes, your older Macbooks should be able to read the partition, and compatibility exists all the way back to OS 8.1 (source)