hey,
a good example of webmail is hotmail, yahoo mail, etc.. basically it's an e-mail account that you access through a web browser as opposed to outlook or eudora.
an intranet is an internal network. for instance, if you play network games with several machines playing at once (trust me, it's fun), you're more than likely on an intranet. a company's computer network is often referred to as an intranet. this may help:
intranet: a single network of computers, generally not connected to anything else.
internet: a 'network' of networks. several networks connected together.
extranet: a single network of computers, allowing (authorised) access to 'outsiders'.
zac