Call me old fashioned but sometimes a book is better than a website.
There are doubtless countless wine books out there (we have quite a few on the shelf between us), however, some have proved more useful that others. Starting out we all found that Hugh Johnson’s Pocket Wine Book was indispensable as a quick reference guide to wine, and the density of information he include is unmatched. It is rare to find a wine where there is nothing to be said at all.
I believe we all own a copy of Hugh Johnson’s and Jancis Robinson’s World Atlas of Wine, although their Concise World Atlas of Wine is a slightly cheaper alternative giving good coverage on European wines. The maps are of great quality and interest in their own right but also help to build a picture of why things taste so different.
One of the reference texts of the wine world is The Oxford Companion to Wine, also authored by Jancis Robinson, although this is more of an encyclopedia than light reading. This book is of an exceptional standard and is used as a core text for the further study of wine.
Please feel free to add any suggestions for further resources to the comments section.