Do applications need to be 64 bit for it to be able to utilize more than 4 gigs? I know that is the case for Windows, so I was wondering if it applies to Macs as well.
I don't think the applications have any bearing on that. It's the OS that decides how much RAM a process gets.
Technically a 32-bit OS can only address ~4gb of RAM, but there are workarounds for that as well.