How to create a virtual floppy drive?
It seems to me that the question asks how to mount virtual images on 64-bit Windows systems, though not stated.
ImDisk accomplishes this result.
If your need is less complex, mounting A: to a folder would work fine.
The main download page for Virtual Floppy Drive is http://sourceforge.net/projects/vfd/. It supports Windows 7 64-bit.
But there are comments on the Sourceforge page saying it does not work in Windows 7 64bit. One user (toantu) found a way and posted a comment further down.
First copy the content of virtual floppy folder to C:\temp\.
Download dseo13b.exe, install ... right click and choose run with administrator, select enable test mode, reboot, run it again with administrator, select sign a system file, type in C:\temp\vfd.sys
Go to C:\temp\ folder, right click vfd.exe, choose properties, go to compatibility tab, select run this program in compatibility mode for XP and also select run this as an administrator, select driver tab, select browse, select vfd.sys, press install and start. Go to drive0 tab, select change, choose A for your drive, OK. Now select open/create, click create and hopefully your drive will be activated in Windows 7 64-bit. You must run all of the above with administrator right by the way, and make sure you have 64-bit version of 2 files vfd.dll & vfd.sys
You don't even need additional software for this. Create a folder called "a", share it, map it as a network drive to A:. No need for additional downloads. I have used this on a lot of legacy systems that need floppy drives to transfer license keys.