Moving this discussion to the Photoshop General Discussion forum.
Don't try for "fast and easy". You will more likely get into trouble - this has been shown time and again.
- See if the manufacturer has released an update that's Photoshop CS5-compatible and get that if so.
- Run the installer if they provided one.
- If the installer doesn't see the new Photoshop, you may have to isolate the plug-in files (there may be supporting files) and copy them manually. If this is the case, let us know here in a follow-up message - the description how to do that can be complex.
- Create a new folder, separate from Photoshop's installation area and one you're going to keep, into which to put manually-installed plug-ins. Point Photoshop's Extra Plug-ins folder at the new folder.
- For those plug-ins without installers, copy your manually-installed plug-ins to your new folder. Restart Photoshop CS5 to get it to see them there.
- Older actions are usually perfectly compatible with Photoshop CS5, but it doesn't hurt to check to see if the maker has issued a newer set.
- For those that you created, modified, or don't know where you got, in your older Photoshop click the set name once to highlight it, then click the little fly-out icon at the upper-right of the ACTIONS panel, and choose Save Actions. Save them in a folder separate from the Photoshop installation area.
- You can usually just double-click a .atn file to load it into the newer version of Photoshop. If not, use the fly-out menu and choose Load Actions.
Move actions, presets, and workspaces from Photoshop CS4 to CS5: http://bit.ly/bZQ0cy
Plug-ins you shouldn't move. Check for the latest updates for your 3rd party plug-ins. You should use the manufacturers installer to install the plug-ins for CS5. It's too easy to accidentally not move all the required files from one version to another. Additiaonally, if you're on a Mac, CS5 is 64-bit and CS4 is 32-bit, many older plugins many not be compatible