One much requested feature not currently in Lightroom is the ability to email files from inside the program. Or is it? With the advent of the Export Action in Beta 4, it is. Originally in this post I suggested adding you email client (Mail in my case) as an external editor, this still works but there is a better way. Create an Alias/Shortcut for your program and place it in the Export Actions Folder (see Below for the location). Now select the images you want to email. Hit CMD/CTRL Shift E to Export and use the following settings:
File Format: Jpeg, Quality:60, Constrain (ticked) Width:700, Length:700, Color Space:sRGB, dpi: 72 and in the Export action select Mail.app (or your email client name). This will open a reduced size and quality copy of your files in Mail ready to email. To reduce the size further you could try Quality 50 instead of 60.
While you can’t add more than one external editor, you can export to as many programs as you like by putting an alias/shortcut to the program in you Export Actions folder in the Adobe Lightroom folder. This is in a hidden folder in My Documents called Application Data on XP and in your User Library on OS X i.e. My Documents/Application Data/Adobe Lightroom/Export Actions or User/Library/Adobe Lightroom/Export Actions