Well, yes it is easy, but it depends very much on which host you have chosen to go with? Which hosting company have you got hosting with?
If you go with someone like GoDaddy or HostExcellence then it is a very easy process and you need to remember when you pick your hosting package that you pick the Linux option and NOT the Windows options or you could run into problems - iWeb works better with Linux hosting. Most hosts offer both? Which one did you pick?
You can download any ftp programme - Cyberduck is good, Yummy or Filezilla.
Also, if you have signed up for hosting then this has absolutely nothing to do with Apple. When you sign up with a host they provide you with all your details so your ftp name, useranme and password - Apple has nothing to do with this, unless of course you have only registered a domain name and have not purcahsed hosting?
Your external hosting problems have nothing to do with Apple themselves - they are not involved at all - you have used iWeb to create your site, but other than this, it is nothing to do with them - you are uploading files to another server so all the information comes from your host and NOT Apple - there is no point in contacting them as they cannot really help you, as it is not their problem and not their information that you need - all needs to come from your host.
It might pay you to actually go and purcahse hosting from a large host such as GoDaddy or HostExcellence and the process will then be easy - they give you everything that you need after sign up and they have very good customer support.
It is an easy process - pick a good host, pick the Linux hosting option, get all your details and use your selected ftp client and upload to your new server - it is as simple as that.