This article is based on Pythian's aricle DOWNLOADING FROM OTN DIRECTLY TO YOUR DATABASE SERVER.
You can find the extension at https://addons.mozilla.org/en-US/firefox/addon/8154/
After you install the extension, clear your cookies and then login to otn.oracle.com and sign in. After you have done this, go to Tools -> Export cookies and save the file.
Then you can copy the file to your server and use wget to download the software. Syntax is
wget --load-cookies=cookies.txt <otn_url>
E.g To download 11gr2 Grid infrastructure software for linux x86-64 bit
wget --load-cookies=cookies.txt http://download.oracle.com/otn/linux/oracle11g/R2/linux.x64_11gR2_grid.zip