Because POSUSB driver disappears from Microsoft site, here you are :-)
[However, I don't recommend it for serious application. The code is buggy and slow (<= 64kBytes/s ??), but it works somehow.]

Point-of-sale driver - /sys+inf/. (posusb.rar) [27k]

Point-of-sale driver - /source/. (posusb.exe) [71k]

Are you using WIN98SE and want to use USBCheck tool? Here is the old version (5.00 Beta), which works well on WIN98SE for me.

USBCheck Version 5.00 Beta. (usbcomp_50beta.exe) [747k]

And here is even older version (3.5)

USBCheck Version 3.5. (usbcomp_35.exe) [811k]

Note: New version of USBCheck can be found at www.usb.org.