I am also running the Adobe CS3 suite & I just upgraded to Yosemite yesterday (Dec. 26, 2014) from Snow Leopard 10.6.8. So I really went for it with this upgrade, of course, taking all the necessary preparations like backups & researching potential problems.
After the upgrade I clicked to run Photoshop & was prompted for the upgrade to Java link just like Eau Rouge indicated. I downloaded it & have been able to run the CS3 programs (Dreamweaver, InDesign, Illustrator & yes even Flash) with no problems thus far.
I am really going to put Photoshop through its paces today & if any issues arise, I will repost back in this forum. But so far all is good. Hope this information helps!
iMac (20-inch, Early 2008), 2.4 GHz Intel Core 2 Duo, 6 GB RAM