Does anyone have some guidelines or links to articles when designing a website that needs to be localized in 20+ lanaguages?
The initial translation isn't so much the problem, rather ongoing maintenance (i.e. when an update is made on the English site, how are people notified that new translations are required).
Thanks in advance!
Many SCMs support triggers that can fire when committing changes and can take action if, e.g. a .pot file was changed, to send email to the appropriate parties.
Here are some web sites dedicated to internationalization and globalization:
http://www.i18nguy.com/ http://multilingual.com/guides.php (they heavily push vendors, but their guides tend to be worth a read)
Google searches on i18n (internationalization) and l10n are often useful as well.
You asked about designing the site though, so I assume you're talking about coding best practices. In general, you want to reuse as much as possible. That means:
Separating all text into resource files (.Net handles this naively, in PHP you can use a template to sub in text, your language may vary)
(Really 1-a) Don't put text in images. This will just cause headaches later since images will cease to be reusable. You'll have to update an image any time text changes and that's often not worth it.
Fluid/liquid layouts are preferred. German text can be 30% larger than English, Asian languages can be significantly smaller than English, etc.
Use a standard character set for web pages (i.e. utf-8). That will minimize rendering problems between the languages.
That's sort of the easy part. The hard part is managing it. Depending on your source control system, you can likely write or acquire a tool that will alert the appropriate party.
Content management systems are built to help you manage changes automatically. Good CMSes are often pricey, however. The above sites can point you at features of those you may look for help you manage your sites.