There is an excellent feature about localisation of gateway pages at webword. The piece details how many global sites have over-complicated gateways in which the user has to find the region that they are in, often through quite convoluted means. The author, John Yunker, explains how the use of flags (as in a country’s flag, not in the programming sense of flags!) can be misleading (”for example, would you use to represent a Spanish-language Web”), and demonstrates how setting preferred language in your browser can be used to automatically serve up the appropriate language.
While this is not strictly an accessibility piece - it’s more of a wider article on usability - it’s certainly something that touches on accessibility. If people cannot get past the gateway page, then it doesn’t matter how good the rest of your content is.