One can attempt embedding videos into an E-mail by using HTML
(as it is the only wide-spread language that can embed videos), but
it is not always definite that it will embed itself - because the
HTML that embeds the video may be blocked or rendered in a way that
does not show the user the video - often for protection.
If the HTML is allowed, then yes, in most cases, videos can be
shown in E-mail.
Most E-mail providers (and E-mail reading software, such as
Microsoft Outlook) will have an option to block HTML, by rendering
it unable to work somehow, or showing the raw source of the message
(with a raw buffer, in which no HTML is parsed into objects or
elements, etc).
Hotmail, Yahoo, and other E-mail providers usually keep this
option on as a default (allowing HTML), but only from trusted
senders of the E-mail, such as contacts. Microsoft Outlook and most
E-mail viewing programs turn the option off as a default (not
allowing HTML).
ALSO
You can Create web videos with an embedded player which can be
placed directly into the webpage.
for Sample players on the web click on the link below.
FOr a Tutorial -- Easy Way to Put Videos on Web Pages, Blogs,
Forums, eBayAuctions, MySpace and More click on the link below
Useful tutorial on its Google blog:
http://funny-video-youtube.blogspot.com