As reported widely, Sun have started allowing folks to download Solaris 10 for free. It's a big download, which you can get at
the Solaris 10 Download Center. There's both X86/x86 imgaes and SPARC images. Both come on either multiple CDs or a DVD. If you opt for the DVD, it comes in several parts that you need to download and combine. I'll post more once I've managed to download the DVD and run up Solaris in a VM.