There's now an Updated MOBIWEB bookmarks-file for use on Kindles, to include better-functioning links for Kindle 3 and some tips on the Kindle 3's handling of some Google areas.
It's explained and downloadable from the blog article at
[The below is left as-is for history of the file.]
I made myself a Kindle file with links for mobile-version websites along with some umbrella type ones, mainly because someone wanted me to recreate bookmarks she somehow lost on her Kindle.
I found some other good ones while doing so, including one that puts your chosen or favorite websites into mobile-style size and layout so you can view them without crashing the Kindle.
I have some tips on the Kindle web browser and these links, at my blog, so will give that link, and the file is downloadable from there, along with some info on browsing modes that can help speed things up or help when the website results have gray translations from color that make the pages too hard to read or when the words are too small.
One thing with email sites like gmail. After you submit a note, you invariably are told by the Kindle (due to an aggressive time-out process?) thet you were unable to connect with the server, but in fact you did and the note is sent. I tend to copy myself on notes so I can tell for sure. I ran into the same thing with notes to Facebook and to the Amazon forums. They're posted even though you get false failure alerts.
The links file is very simple, but I hope it'll help some who haven't experimented much due to the slowwwness of the Kindle browser and the cellular connection, which I think is probably throttled to save $.