I have been bothered too many times to download oracle installer from otn.oracle.com, whenever i had to do so, i was reluctant just because OTN force us to download their installer using browser, i hate browser based huge files download, my love "wget" always support me...i was thinking that wget has a limit to do this task until today...i found the solution... just arguments usage !!!
1. You have to browse until http://www.oracle.com/technology/software/products/database/index.html
2. select your choice of OS & Oracle version to download.
3. On clicking the link for download it will ask you to provide OTN's username,password that you must have to proceed, if you already singed it, provide it, otherwise you have to create it (its free) :p
4. After providing username,password it will start download your choice oracle installer, now you have to right click on downlaod bar "i am using firefox" & copy the "download link"
5. open command prompt/terminal and use wget as following...
wget -c --http-user=your-otn-username --http-passwd=your-otn-password http://download-llnw.oracle.com/otn/solaris/oracle10g/10201/sol64/10gr2_db_sol.cpio.gz