There are just numerous options, some of which can go through email accounts, such as Yahoo - I'm sure that you'll receive plenty of different recommendations, so my purpose is not to give you the BEST choice but a consideration.
My wife & I are currently using Cozi (Check HERE) - has been working well for us - good luck in your choice!
The IPad Forum is a Community of members from all walks of life and from all over the world coming together to share our experiences and to help each other learn about this wonderful piece of technology the IPad.
There is a wealth of information already here in the many threads we have so doing some searches will answer most of the questions that you have. If then you can't find the answer you are seeking, then by all means post your question. You will find many friendly and informed members here only too willing to help you.