Everyone, how do I type an hash-tag?

[Louis The Proud Britisher]

And before you say "It's not 'an' hash-tag", it's Old English to say "an" before a word beginning with "h".
Sometimes, the old ways are the best. :-)

[ฬнïzzz!]

You create a hashtag simply by prefixing a word with a hash symbol: #hashtag.
Simply type a phrase of the form “#topic.” Do not put any spaces in the phrase that you want to turn into a hashtag, because the hashtag begins with the “#” and ends with the first space.

When creating a hashtag for something that may consist of two or more words its a good idea to use the "CamelCase" format to maintain legibility.
The idea is to join words with each words initial letter capitalized. For example if I wanted to create a hashtag for south Africa, I would type out: #SouthAfrica instead of #southafrica
More here http://twitter.pbworks.com/w/page/1779812/Hashtags
http://www.wikihow.com/Use-Hashtags-With-Twitter