To simplify usage for those unfamiliar or uncomfortable with the Mac OS X command line, I have created a Desktop Application version of the pasteboard server. Its features are identical to the command line version. The name of the application version is PasteServer. To run this version, download the zip archive, unzip it, and place it into your /Applications folder. Run it by double-clicking the application icon.
Start the server by clicking the "Start Pasteboard Server". Once the server is active, copy text and image items into the Mac pasteboard (Command-C). Then run the client application (PasteCatcher.app) on the iPhone. Once the application receives the data, press the Home button and navigate to whichever application you need to use. Use the built-in iPhone paste support to paste that data into (for example) the Notes app (use it with lists and other text copied from the Mac), into Safari (handy for pasting URLs), into Mail (works great with pictures copied from Preview), and so forth.