I have to point out that this operation will not always be easy or free. And certainly it will be tiresome task in some cases. This is due to several reasons. Many people get this kind of job where the client asks for him to convert the existing page “normal” HTML / PHP on one with content management system, in our case Joomla.
Certainly, you will have to deal with three problems (TCL):
Template
If client wants the same, you have to do it based on a framework, it will be quicker and simpler solution. And most importantly the most effective, than building from almost scratch. If a customer wants a new template, then you have easier – choose from thousands of already available like our Gavick (depending on the version of Joomla!) and install it.
Content
The key of each page is its content. If the customer wants, and usually it is, leave the “old” content, you need to move it. If there is few pages, will be cheaper simply manually copy – copy-paste method, also with the support of the mass content component (www.baticore.com). It help make the creation of sections, categories and articles much easier because it enables the developer to create all of these items on a single screen without having to jump back and forth in the control panel. Unfortunately, no version for Joomla 1.7 and it is unknown whether the developer will do it. If the subpages is too much, or you have a little time, you may be wondering on some automatic solution.
Then with the help can come Component “HTML 2 Articles” (php-web-design.com), unfortunately it costs £50. However, once purchased, you will serve for the next 6 months. It can convert the pages to Joomla! 1.5, 1.6 or 1.7. Including titles, meta fields (keywords and description). If it turned out that the extension has a problem you can try before replace “old” to plain HTML page using a free program such as HTTrack.
Internal links
Will be much work here, there is currently no way to automatically update the links from the original html page for links to articles in Joomla because Joomla pages are connected by id numbers, article, which differs from the way they are combined in a format HTML, using the page name.
The only option which I see is to use the component, which will be able to update the links within the articles, and so have to use component who can search and replace in any table in your database – like DB Replacer (nonumber.nl). You should also use online tool Link Checker (http://validator.w3.org/checklink), which will tell you which addresses refer to error404 error page, remember to completely deactivate the old page before checking.