Until awhile back, I had a network managed by a T-1 Modem and router. I was able to share files on my computer and also my printer with my wife. Then I purchased a Verizon MiFi device that doesn't support file or printer sharing. I thought I would solve the problem by purchasing a WiFi capable printer...ooops! It does not appear that I can enable WiFi and MiFi at the same time, THUS sharing is out. Is there any solution, other than purchasing a USB printer sharing switch and forgetting about file sharing?
MiFi is WiFi, it stands for My WiFi and should allow you to STILL share files and printers as long as the devices are all within the same subnet (which they will be)

Did the previous router have a program that enabled you to share files and FOLDERS like the linksys/cisco routers do? (Network Magic) This may have been the source of your file/print sharing and the Windows one was never used.

Make sure you have enabled file and printer sharing in the Network and Sharing center under advanced sharing settings for 7, or on the main page for VISTA.

If you are still running XP, make sure you have run the Network and sharing wizard.

It is also important that if you have a mix of XP, Vista or 7 machines that all machines be on the same workgroup. This makes sharing and finding each others computer easier. 7 is not so BAD at discovering network devices but XP is terrible and this helps it along.

Also I have found this through a quick Google search.
http://www.evdoinfo.com/content/view/2911/63/
It is a guide to setting up the Verizon MiFI to use file/printer sharing.

Best of luck
Kurtis