Opera released a new version of their browser (9.27) that fixes two remotely exploitable vulnerabilities (http://www.opera.com/support/search/view/881/ and http://www.opera.com/support/search/view/882/). The update can be downloaded from http://www.opera.com/download/.

 
Microsoft also released advance notification about this month's black Tuesday. And it looks like it will be a busy day for sure: Microsoft announces 8 security advisories (5 critical and 3 important), as well as some other non-security patches. More information is available at http://www.microsoft.com/technet/security/bulletin/ms08-apr.mspx.