Simplest way to transfer files from PC to Android device (wireless)

What's the simplest way to transfer files (often around 100 MB) from PC to Android device, **with wireless connexion** ? Should I use an application for this? *Remark 1 : I want to set "wifi=off" after the file transfer is done, because I never use it except for the file transfer. Moreover I really would like to do a direct transfer PC -> Android device ; no Dropbox or similar tool.* *Remark 2 : I have a Samsung Galaxy 3.6 Player YP-GS1CB (limited to Android 2.x as far as I know)* *Remark 3 : If possible, I would like to be able to see the Android device's microSD card filesystem from computer, access to subdirectories, copy files there, etc. Would a FTP server on the Android device be a good way to do it ? If so, with which app?*