Do you really need to uninstall them, or are you worried about security and want to disable them to prevent problems? Opera for the anvil chorus. For Flash, you can install ClickToFlash or ClickToPlugin in whichever browser you use, or you can go to /Library/Internet Plug-ins and delete the Flash Player plugin from there. For Java, you can use ClickToPlugin as mentioned above, or you can go into your browser's settings and disable Java (which is sufficient for protecting you from the Flashback malware, and in fact every piece of malware which has yet attempted to use Java vulnerabilities). If you wish to completely uninstall it, don't. While it wouldn't necessarily be a bad thing to not have it, it would take more work than you should probably attempt for little or no benefit. If you want, you can disable it system-wide, via the Java Preferences app in your /Applications/Utilities folder.
Java for Mac OS X 10.6 Update 17 delivers improved security, reliability, and compatibility by updating Java SE 6 to 1.6.0_65. This update enables per-website control of the Java plug-in within Safari 5.1.9 or later. If you're running Mac OS X 10.6.8 though, Apple outlines that only iPhoto 9.2.3 or lower is compatible, which is not available on the App Store. If you could locate your original discs that came with your Mac, you could reinstall iPhoto from the second disc titled 'Applications Install DVD'.