Not much is known of Office 15 other, but we do know that it has reached it's Technical Preview stage. The next version of Office promises to make it's way not only to supported Windows devices and Windows Phones but also to the Apple iPad. So while we are still waiting to see Office 15 on a Windows device, the touch based Office suite has already been sited running on an iPad.
Office for iPad has an interface similar to the OneNote iPad app with it's Metro UI influence in display. We would probably see a similar UI as Office 15 makes it's way to Windows 8 and Windows for ARM devices.
It is possible that Microsoft may reveal Office 15 soon. Specially for the Windows community will get to savor it before the launch of the Apple iPad 3. With Office 15 expected in line with the Windows 8 release it may be unlikely to see it sooner on the iPad.
There is no news on the pricing of Office for iPad, previous rumors suggested that Word, Excel and PowerPoint will be individually priced competitively with Apple's own Pages, Keynote and Numbers apps. However if the leaked image is true it looks like the entire suite will be packed into a single apps.
Currently there is no news if Microsoft Office will make it's way to Android tablets. For now Microsoft looks to take advantage of Apple's tablet popularity while the release their own offering to the tablet market later this year.
source - The Daily