http://www.ps3hax.net/2011/02/how-to-transfer-large-files-from-pc-to-ps3-at-lan-speeds-100mbs/#axzz1E31waPjZ

Tried it and it works pretty well. Using filezilla and so far only problem is that although number of connections is set to 10, the first 7 are frozen on connecting and only the last 3 connections transfer files.
But still ftping to ps3 is a lot faster and more stable! only had one disconnect so far, with wireless connection I was getting dced all over the place.

Thsi does require changing your network adaptor settings, but if you are going to stp to your ps3 regularly you may want to buy a network pci board and use that only for your ps3, otherwise you will be changing your settings all the time, not a big deal but may get annoying if you got to do it all the time.