iDOS, DOS Emulator: Windows on iPad Installed
iDOS is a full DOS emulator that is based on an open-source DOS emulator, DOSbox. It is a universal app that has PC keyboard support, mouse support, multiple screen modes etc.
Over at TouchArcade, a member of their forums has managed to install and run Windows 3.0 on his iPad and is now playing Solitaire on Windows 3.0.
iDOS app was first approved by Apple for the App Store and was available for just $0.99, but just a few hours later it was pulled down. Even if Apple doesn’t allow iDOS in the App Store, you can still grab it from Cydia for your jailbroken iPhone 4, iPod Touch 4 or iPad. It is available on Cydia by the name of DOSPAD.
Download DOSPAD from Cydia to run Windows 3.0 on iPad.