One of the best ways to get the best bang for your buck on your iPhone is by using it to track your daily tasks and events. iPhone can make you productive as long as you use the right tools. Calendar apps on iPhone allow you to do just that. Whether you are looking for a calendar that keeps track of your tasks or biological cycles, there is an app for that. If you are looking to transform your iPhone into a mobile calendar, here are 10 best cal apps you should try:

Pocket Informant: one of the most powerful task management tools in iTunes. The calendar combined with the ToDo list feature makes it easy to keep track of your daily tasks.

CalenGoo: comes with a killer interface and makes it easy to manage your tasks and events on Google Calendar right on your iPhone.

Saisuke: a very powerful calendar app that could come in handy for project managers and business professionals. Works with Google Calendar as well.

Luna: a fun little app that provides you with the lunar calendar and lunar charts right on your phone.

iPeriod: a great application for women. Allows them to keep track of their period cycles. It also shows you emotions per each week as well.

Bill Pal: have a tough time remembering when to pay your bills? Bill Pall lets you set up alerts and stay on the top of your bills, which is very important especially in these tough economic conditions.

Holiday Calendar: great little app if you have trouble remembering the holidays. If you are a non-native American, it’ll be much more useful.

Pocket Luach: a calendar designed specifically for those within the Jewish community. Converts to/from Jewish Calendar. Displays all Jewish holidays as well.

Catholic Calendar: designed for the Catholics, allows you to keep track of their holidays, so you’ll never miss an important religious date again.

Taqhvim: a Persian Calendar for iPhone that is designed for Iranian Americans. One of many cool international calendars out there.

What’s your favorite calendar app for iPhone?