Gary, do you want the recipient to be able to look at the model in SketchUp? Or do you want them to just see images of what you've drawn?
WiZeR's advice is correct but you should be aware that anything you upload to the 3D Warehouse is out there for anyone to take. You could also use a service such as putfile to upload the SKP file. The recipient can then download it within some fairly short period of time after you give them the link.
You can't send files by PM on this forum. To send via email, you attatch the .skp file to the email and send. If by 'plan', you mean a 2d .jpg file, then you need to click file>export>2d Image and save the file. This can then be sent in the same way via email.