I'm not sure which section to put this in, but I have 3 questions:
1 Is there any form of CMS software that can be used as an add-on to existing websites rather than having to design the website from scratch in the CMS software?
2 If there is no CMS software that can be used as an add-on, what is easiest to use CMS package? (I come from a design rather than a programming background.)
3 If we buy a CMS package, will this also be useful when we come to tackle ecommerce?
At the moment, we are trying to break into the web design business/learn the basics by offering brochure websites but would like now to expand and offer CMS and - eventually - ecommerce. We currently use Microsoft Expression but some clients would like a news page for their website (accessible from the main menu). We recently had to turn away a client who wanted to update their own menu items for a restaurant site.
Many thanks to anyone who takes the trouble to answer.

1. Not that I know of, and I've used quite a few.

2. Try CMS Made Simple, I have found it extremely easy to use. It runs on the smarty tag template engine, so no coding knowledge is needed. It has tons of modules and tags that you can add on, and it even has a module manager that allows you to add modules from within the admin interface with no need for FTP even. There are tons of good ones out there though, you really have to find what works best for you. a fully functional ecommerce store with a large-ish catalog is a different story though.

3. when choosing a pre-built system, you really have to look at the specs of the project before you decide. I suggest playing with multiple systems and choosing a blog engine, a CMS, and an ecommerce engine seperatly. you will rarely find a system that does it all in a manner that will suitably meet all of your needs.

whatever you decide to go with will be a big step-up from Microsoft Expression. Expression is really not much greater than front-page. let me know if you have more questions, I have worked with systems written in just about all the major languages.

Drebeta - thanks for a very helpful post and for the tip about CMS Made Simple. Will check it out.

Have now started checking out CMS Made Simple, and wonder if anyone could tell me:
1 Can it handle pictures - eg a different prospective client wants to be able to upload 40-50 pictures with brief descriptions?
2 Is the $4.99 per month per website or does this cover a web designer with multiple clients?
3 Could we link 1 page (eg a news page) created in CMS Made Simple into a website created in Expression?
Many thanks.

1. yes, it has an image manager. are you looking to build a gallery, or do you just want images available to insert into pages?

2. not sure what you're talking about here. I typically download the source and install it on my own, or my client's, server.

3. you could, but if you're going the CMS route I don't know why you wouldn't put the entire site into CMS. Trust me, once you move into CMS you will absolutly hate Expression and wonder why you ever bothered with it.

If you're just looking for a news page that you can update via a web interface, try a blog engine like WordPress. WordPress is also very robust, and you could use it as a CMS as well. However, it does require some knowledge of php.

I have used drupal as a "Add-on" to a existing website. Say for example there are only two pages in your site you need a cms for that perfectly fine. Naturally though you will have to create a template that matches your site for drupal to use but thats pretty easy. Haha i have actualy used drupal to create a single page on a certain site http://www.spurcreative.co.uk/prop_hire/ all the other pages on this site are HTML