When I paste in my single spaced Signature (block) into a meeting invite it is received by the recipient double spaced. What needs to be done to have the Signature appear single spaced?

Sounds like a standard HTML formatting issue with the signature.  You might want to recreate your signature, creating new lines with Shift+Enter instead of Enter.  Try these links:

http://office.microsoft.com/en-us/outlook-help/remove-double-line-spacing-from-a-signature-HA102019187.aspx

http://www.howto-outlook.com/faq/signaturelines.htm

Hi,

Did you solve the issue with the help of Anthony provided?

Here is another similar issue may help you:

http://slipstick.com/problems/messages-are-double-spaced/

Note: Microsoft is providing this information as a convenience to you. The sites are not controlled by Microsoft. Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. Please make sure that you completely understand the risk before retrieving any suggestions from the above link.

If the issue persists, it is more Office components related. Please also post this issue on Office forum for further assistance. Thank you for your understanding.

http://social.technet.microsoft.com/Forums/office/en-US/home?category=officeitpro

Best Regards,

Eason Huang