How do I print from my ipad to a canon pixma mg6150 printer that is connected to my home pc (via wifi)

As it's not one of the HP printers that support AirPrint, you will need an app in order to print to it. I don't think that Canon have their own app, but there are a number of third-party print apps e.g. Print n Share, PrintCentral etc.

I use Printopia which allows me to print from my iPad2 to any printer that my laptop has access to. Works very well and I highly recumbent it to you.

Peace, David

I have a Canon MX6150 as well. I downloaded the free Canon Easy-PhotoPrint app from the App Store. Then to print, select "open in" > select iEPP > select papersize > select plain paper > select print. Succes.

MX6150 must be MG6150.