Downloads listed here are for officially verified releases. If you're not sure which you need, you probably need the 32-bit version 3.x ISO. Alternate ISOs, including daily snapshots, are available here.
N.B. - Always compare the MD5 checksum for an ISO after you download it and before using it to make a bootable media, etc.
|3.3.1 64-bit||bccd-3.3.1.amd64.iso||728 MB||February 18, 2014||(md5)|
|3.3.1 32-bit||bccd-3.3.1.i386.iso||671 MB||February 18, 2014||(md5)|
|3.3.0 64-bit||bccd-3.3.0.amd64.iso||663 MB||October 25, 2013||(md5)|
|3.3.0 32-bit||bccd-3.3.0.i386.iso||615 MB||October 25, 2013||(md5)|
You may also want to download the build_bootable_usb.sh script for making bootable USB under Linux.