I am using Sun Virtual Box on CentOS 5.3 . Well i cannot mount any usb drives on guest OS.
I tried modifying /etc/fstab file and all necessary filters and USB controllers are enabled , and usb is unmounted in host os but still cant enable USB on guest.So now i cannot install any os on my pendrive. How can i have flash drives enabled ??? plz help

Did you check dmesg entries whether USB driver detected?

In the 'USB' section for the 'Settings' on this guest, did you add a filter for the device? If not, it will never work.

If not, go in and add a filter for it, and it should at least detect.

One of the few things that I use VirtualBox for is syncing my wife's iPod via iTunes. Don't worry about the host machine loading and binding a driver for the device . . . it shouldn't affect VB's ability to latch on. It actually makes it easier to set the filter, as if the host has already detected the device, it has it listed in a "ready" drop down of filters to add.

Have you studied the VirtualBox User Manual? It's well-written and helpful.

Which version of VirtualBox are you using?

You are right not to mount the USB device on the host at the same time as on the guest but it is a good test to mount it on the host to see if it has been detected etc.

Yes i have added the filters and its detected in host and on virtual box also it shows 1 active also in virtual box

Seems likely VBox is connecting the real USB device to the virtual machine. Which OS are you running in the virtual machine? Which commands have you used in the virtual machine to investigate the virtual USB device? What is the real USB device?