I think it depends on what you want to do.
Topgunn - George won't work on your iPhone for a start.
But if you just want something to list jobs on specific days you could either use a spreadsheet, or to view on your iPhone, Google calendar. Both of these options are FREE.
I think the best way to approach it is to think what is the least technical way of doing things that works for you? I've seen some people implement software systems and end up spending all their time trying to satisfy the requirements of the software, rather than the other way round!
To declare my interest: I work for a software company that has written software for cleaning companies, which you can see here:
http://home.malinkoapp.com/cleaning/ It starts at £5 per month
Also, do you want to have a customer database and use it for storing various bits of information about your customers? You could use our database to track marketing campaigns for instance.
Or would you like to take a photo and store this image with the job record?
Our system will not only work on your iPhone, but also on your colleagues Android phone.
If you implement a software system that is designed to handle your information, it can make your life easier in ways you didn't realise could happen. Do you want to be able to see your list of jobs for the day on your phone and send your next job a text at the touch of a button? What happens when you have staff and you want to generate job sheets for them? I could go on, but I won't!