Yes and no....
PC and Mac speak different languages, both in terms of the filesystem and the file structure.
While your Mac will generally read almost every hard drive filesystem, Windows can't read the Mac's HFS+ format. FAT32 is the best "between the operating systems" filesystem you can use as both can read and write to/from the drive.
Even if your drive is already FAT32, the next problem you'll encounter is drive naming and file paths thanks to different file structures. What was once recognized on your Mac as being /Users/yourusername/Library/Pioneer/rekordbox is now found in C:\Users\yourusername\AppData\Roaming\Pioneer\rekordbox within Windows. And that's just the main file location. The database itself is a file which stores the path to each song in your collection. Even if that location is external, you'll need to find/replace the path with the new path.
One thing I have not yet tried, is using the external database mode between two operating systems. You can find instructions on how to do that here, but I don't recommend you do that with your ONLY copy of the database as it may fail, and fail horribly (which is actually my prediction).
The short of it is there is no "best / easiest" way to migrate between operating systems.
