You'll have probably found it by now, but for anyone else, on Windows it's typically under your Windows install directory in .\System32\drivers\etc\hosts. On Android it's under /system/etc/hosts, but you need root access to edit it.

Edit: just remembered, you'll probably need elevated access on Windows boxes as well, and this can get a bit tricky on Vista. Right-click on your notepad icon and select "run as administrator" (which you'll only have if your account has admin privileges). Then open the hosts file from the above path inside notepad and edit it there.

Am going to refer you to google since I do not run Windows or Android.

Unless what I have read is unusually misinformative, though, it is possible on both. (On Android you need access to root.)