I don't know of any apps but I use the iphone and have been since August of
last year.  I absolutely love it and don't see me changing to another phone
any time soon.  It does take some getting used to and text entry can be slow
going at first.  I was kind of forced because I wanted it and couldn't keep
another phone in service to see if it would work for me.  That being said, I
will admit that I manage my contacts from the computer and also email.  I do
however use the iphone for text and some short email.  I also have entered a
contact or 2.  Thee internet is good and all and all I am pleased.  It isn't
for everyone and if you are easily frustrated it might not work out.  Don't
give up or throw it because they are expenssive.  I'll help you with it if
you would like.  I'm not an expert but the iphone works and fits into my
life perfectly.