How should I create a network share between my PC and Mac?

[baydude]

I have an ASUS RT-N65U router that has a USB port for a network drive. I'd like to have my WD Passport hard drive accessible from both my PC and Mac. How should I format the hard drive and how do I access the hard drive from both computers?

 

[VirtualLarry]

Look in the manual for the router for which external USB HDD filesystems that it supports.
Some routers and NAS units, require you to re-format to some internal native Linux format before it can be used for network sharing. (Most common with NAS units.)