I wish to create a simple portal website.
By simple I mean:
I have some basic html knowledge and I wish to learn whatever is necessary to make the portal look like it's been made in 2010 and not in 1996: css? anything else?
How would you recommend to proceed? Which resources (website, book, other) would you advise?
if you wish to build it from scratch, I recommend you to read something like
Learning Web Design: A Beginner's Guide to (X)HTML, StyleSheets, and Web Graphics or HTML, XHTML, and CSS Bible depending on witch will fit best your current web development knowledge. Check the books inside for a better understanding of its contents. You may even find other good books on the subject, since HTML and CSS are well covered topics.
For the coding part, I recommend Aptana, it's open source, extensible and very useful when coding HTML and CSS among others.
If you wish to do less coding or having more flexibility out-of-the-box, you may consider using a content manager such as Joomla!. There are many content manages out there, MamboOS and Drupal are other examples.
It will allow you to easily change the contents of your pages and provides some nice modules/plugins that may be useful for you, e.g menus and site search.
With a nice simple template (you may even got lucky and find one for free) it may be the shortest route for your goal.
Not sure what stage you are at. Hopefully you have some sort of drawing or web page already since you know html.
Just put it on one page. How much relevant text could you have about a list of hyperlinks? Google has managed to not put a lot of stuff on their home page.
If you spend more than one week on this project, hire a web designer; unless you're having fun ;)
CMSmadesimple is great for simple sites - easy to work with, can create sites quickly. With a little HTML experience, you can do a lot.
Drupal, Jooml a and the like is definitely a step up from there - products that have a good number of plugins & visual templates that can be endlessly customized to your needs. You can develop (or have developed) a custom application that works inside of these environments. In addition, many of the commercial template providers (Joomla is pretty good for this - yootheme, joomlart, rockettheme for example) offer quickstart packages where you can easily duplicate the demo (content, images, modules, etc) with a single install. From there, you can remove / modify to suit.
Which to choose? Depends on your situation. I tend to like to set a foundation that I can build on - so I choose drupal / joomla type solutions so I only have to learn it once. Sure, there is a learning curve here - but once you get the hang of it, adding functionality to your site becomes much easier than starting from scratch again.
Drupal, as mentioned above, is a powerful Content Management System (CMS) that has more features off the shelf than Wordpress (Drupal comes with blogging, forum, pages, menus, user login/permissions). Wordpress takes some hacking and many plugins to operate like a CMS. I like both for their strong open source development, but I'd stick with Drupal for site building and Wordpress for blogging. Joomla is comparable but add-ons aren't free.
If you want OpenID login functionality like this and other StackExchange sites have, Drupal has a much more developed open source OpenID module than Wordpress, unless you decide to bank on commercial providers like Janrain for Wordpress.
You can also use the hosted version if you don't want to install anything yourself: http://drupalgardens.com/