People used to use AAO template for electrodeposition of nano tubes....

The most common is anodic aluminum oxide (AAO) or polymeric membranes like polycarbonate (PC) filter membranes as templates. These can be purchased from Whatmann or Millipore.

http://www.whatman.com/Membranes.aspx

There are a few really good reviews on this topic but the one below is particularly helpful for membrane grown nanowires.

http://pubs.acs.org/doi/abs/10.1021/ic0601384

Article Template-Grown Metal Nanowires

I will agree with Christopher, AAO templates are the most common way to do so for metals. It is a rather "easy" method if you want to make the templates your self, it is though a long process. Generally speaking in order to do deposition of metal within the AAO template you need a conductive material (usually Au) below your template for the electrodeposition process or you can use comercial AAO and deposit a layer of Au below the open pores.

The paper below has a very good description of the fabrication process of Ag nanowires within comercial AAO templates and I believe it is a good start if you want to use AAO and understand what is going on there :). The difference is if you want to grow Ag on a different type of substrate i.e. S iwafer where you need to deposit Au on Si then deposit Al, then do anodization of the Al in order to make the AAO template and then Ag electrodeposition. Kinda a longer process than simply buying comercial template :).

Hope it helps.

http://iopscience.iop.org/0957-4484/17/2/037