Can I use my older airport express with an ext drive to backup time machine wireless, Can I use my older airport express with an ext drive to backup time machine wireless

An AirPort Express will not support a hard drive.

Maybe you mean AirPort Extreme?

To avoid more confusion, give us the model number of the device that you are asking about. It's on the side or bottom of the Airport....starts with an "A" followed by four numbers.

Thanks for the clarification.

While you can connect a USB hard drive formatted in Mac OS Extended (Journaled) to the USB port of the AirPort Extreme, I would not recommend that you try to use Time Machine with this arrangement, as it is not officially supported by Apple.

You might want to review this recent Apple support document to confirm:

http://support.apple.com/kb/HT2038

can I then connect a HD with itunes music and photos?

Now we are drifting from the original question.

Im alreadty using the HD attached to my Mac Pro...can I just connect it to the Extreme and access it wirelessly with any device on the wifi net?

You may get another opinion on this from another user, but I do not recommend this either, based on a number of experimens over the years with this.

Access to your data on the drive will be much slower. iTunes will tend to "lose" the library this way and you will have to re-point the iTunes application at the library on a regular basis.

Things are even worse with the iPhoto library. The experts over in the iPhoto support area strongly advise that you do not do this, since any break in communication between the iPhoto application and iPhoto library can easily corrupt the entire library. A wireless connection makes things even more dicey.

My advice......Use a drive connected to the Extreme for storage or other backup copies of data.....not for "working" files or libraries.

But, you may get some other opinions from users here.