Generally speaking, all you need to do is literally copy the folders that contains the files that comprise the Virtual Machine from the Windows Host to the Mac Host. You can then turn each VM's Folder into a Virtual Machine Package by adding the .vmwarevm extension. This extension is hidden by default when VMware Fusion create the Virtual Machine's Package and you can hide it from the Get Info Sheet. The following .vmx configuration file options are the VMware Fusion created defaults...
powerType.powerOff = "soft"
powerType.powerOn = "soft"
powerType.suspend = "soft"
powerType.reset = "soft"
In VMware Workstation/Player they are set to "hard" and you might want to set then to "soft" so as to conform with VMware Fusion defaults, however it's up to you. If you don't modify these power options then you can get the defaults by pressing the Option key while selecting the Virtual Machine menu in VMware Fusion.
The other things to be aware of is hardware that doesn't exist on the Mac that existed on the Windows Host, you'll have to make appropriate modifications to the virtual hardware that was pointing to a physical device that doesn't exits on the Mac. Also any FQP that exist in the .vmx configuration file and any .vmdk files will need to be modified.
I use VM on all three Host, Linux, OS X and Windows and move some between them and some are Packaged and some are not and when not Packaged under OS X I simply just execute the .vmx configuration file. This starts the VM and placed an entry in the Virtual Machine Library. You can also just drag & drop the .vmx configuration file onto the Virtual Machine Library or use the File > Open... command.
Also be aware that on Windows VM's you'll probably have to reactivate Windows and other software that used a hardware calculated hash for activation.
