Yes, there is (sort of). Google has a new feature – the Translation Toolbar – that you can install on your site and it will automatically pop up for the user if their browser’s language isn’t the same as your site’s language. (Then they just click 1 button to translate your page before their eyes.)
Admittedly, I’ve only tested it on one of my sites (not blogs) and liked it — but didn’t implement it for lack of time for thorough testing. It’s on my to-do list for another day.
And so, I haven’t used it on a WP blog yet, but I would imagine it’s easy to include. For example, since it’s just a snippet of Javascript code, there must be a plugin somewhere that allows you to easily insert any snippet of code into your WP pages, so that you can add this. You can of course edit your Theme files yourself, if you feel comfortable.
Not that this is not the Google Toolbar Translation feature — that’s part of the toolbar that a user chooses to install on their browser.
Check it out: the first item here.
-WCC