If your account is posting spam then it means a third party website has access to your profile. Change your password so they no longer have access. You should also be wary about signing into third party Twitter sites as a lot of them are illegitimate and store your details.
Unspam it yeah
No, you can't email someone on Twitter. You can direct message them (if they follow you), however, which is kind of like emailing someone.
On Twitter, you can invite your msn contacts to join Twitter.
There is no such thing as a "Twitter spree." Maybe it's a reference to someone using Twitter excessively.
To do a retweet on Twitter by someone famous you can either use Twitter's in-built retweet function or type 'RT@username' where username is the famous person's username on Twitter and press 'tweet'.
FW on twitter means to forward something to someone else
You have to have Twitter mobile enabled.
No this is not possible.
no because you don't have a twitter account yourself
There is no way of knowing if someone visits your Twitter.