MobileMe bookmark sync with Opera
Not with MobileMe's built in sync function, it only works with Safari.
You could use Opera's Link, which might work ok for what you're after -

Can I use other browsers to access my bookmarks?
Yes, you can log into a web-based user interface using Opera browsers, including Opera for Mac/PC, Opera Mobile or Opera Mini. You can also access your bookmarks using other Web browsers like Internet Explorer, Firefox or Safari. (Opera faq)