There are a number of ways to connect an iPad to a projector to display photos, video or give a presentation.
iPad to TV or Projector Adapter Options
As noted in the original iPad User’s Guide (see page 131) the early iPad models, iPad (Wi-Fi) and iPad (Wi-Fi/3G/A-GPS), can be connected to a projector or television to display photo slideshows or video by using “the Apple Composite AV Cable, the Apple Component AV Cable, or the iPad Dock Connector to VGA Adapter.”
The iPad 2 models, the iPad 2 (Wi-Fi), iPad 2 (Wi-Fi/GSM/GPS), and iPad 2 (Wi-Fi/CDMA/GPS), and the current iPad 3rd Gen models, the iPad 3rd Gen (Wi-Fi Only), iPad 3rd Gen (Wi-Fi/4G LTE AT&T/GPS), and iPad 3rd Gen (Wi-Fi/4G LTE Verizon/GPS), support the earlier adapters as well as an HDMI-equipped “Apple Digital AV Adapter.” The Apple Digital AV Adapter is compatible with the original iPad models as well.
All iPad models support 480i and 576i via the composite adapter and 480p and 576p via the component adapter. The iPad 2 and iPad 3rd Gen models also support for up to 1080p video out via the VGA adapter or the new HDMI-equipped Apple Digital AV Adapter.