There's numerous ways to achieve this goal, although I don't own an iPad so this list is in no way exhaustive. See if any of them work for you:
You can use the Camera Connection Kit here ($29.99):
http://store.apple.com/us/product/MC531?mco=MTc0MjU1ODU
You can use MobileMe gallery ($99 per year)
You can email the pics to yourself from your phone (although they are likely to be resized) ($free)
If you have a Mac you can use Preview to get the images off your phone, then iPhoto to catalogue them, then sync to iPad through iTunes ($free)
You could upload them to an online storage service like Flikr, then browse to them via Safari on the iPad, press and hold on the image and then "save image" ($free??)