You can also get a network tuner like the HDhomerun and bypass PCs and Macs. There are two methods/apps to stream the channels to your iPad that I am aware of:
1. TV Streamer with Goodplayer - my preferred combo. TV Streamer talks to the network tuner, does the initial channel scan and when you select a channel, it tells the HDhomerun to stream the channel to Goodplayer. Pros: channel scanning works better than InstaTVPro, automatically adds channel logos to each channel. Cons: logos can be wrong, needs Goodplayer to get the stream and play it back.
2. InstaTV Pro - just checked this one out last week. Note that it must be the Pro version, not the free or standard version. I made the mistake of buying the standard version, and the developer was kind enough to give me a promo code to get the Pro version.
Set-up scans channels, then you can select the channel and it plays back within the app. Pros: all in one app Cons: no logos (although it says it does), channel scanning a bit hit and miss - had to scan multiple times until I got most of the available channels.
These will also work from a tuner on a PC, InstaTV needs its server installed on a Windows Vista/7 machine. TV Streamer only works with the HDHomerun tuners, but there are other streaming methods for general tuners in PCs.