While OpenSolaris still lists them, I couldn't find checksums for Oracle Solaris on the download page. Fortunately I found their E-Delivery site, although it's a bit cryptic to use.

For my just downloaded sol-10-u9-ga-x86-dvd-iso.zip I have to choose "Oracle Solaris" and "Oracle Solaris on x86-64 (64bit)" and then select the "Oracle Solaris 10 9/10 Operating System Multi-Language Media Pack". Now I'm presented with 3 different downloads (not necessarily related to my selection earlier), each of them has a "Part number.

By clicking "View Digest" I'm presented with the MD5 and SHA-1 digests of those part numbers (with .zip added) - so I have to switch back to the other window again to find out which part number I'm looking for at the digest site. Oh dear. Well, here are the digests for the current Oracle Solaris release:

V22438-01.zip (sol-10-u9-ga-sparc-dvd-iso.zip)

    MD5       3A24F5746EBAB5F254C359F979E644F7
    SHA-1     98953B5AECDE175831003A44FB5752B9C6E783AC

V22441-01.zip (sol-10-u9-ga-x86-dvd-iso.zip)

    MD5       CB55F4B7AF194F6378AA5F304F3EA8FC
    SHA-1     5701FC18978337B163AD50F06DD0460F90E9AF8F

Let's all hope they're adding those checksums to the download page again...