You can use Google's Analytics for Mobile Apps with MonoTouch with a few simple steps.
You will need to get:
A sample project can be used as a reference on how to use the software.
1. Add a reference to the GANTracker.dll by selecting "Edit References" in your project, click "Add" to add it to your project:

The above brings the Managed/C# API into your program. For the program to work, you need to make sure that you statically link Google's provided libGoogleAnalytics.a. This library in turn requires that your program links in the CFNetwork framework and the libsqlite library.
To bring these two components into your program, select your project options (either from the Project menu, or by right-clicking on your project and selecting options). In the iPhone Build Tab, you need to add the following command:
-gcc_flags "-L${ProjectDir} -lGoogleAnalytics -lsqlite3.0 -framework CFNetwork -ObjC"
The panel should look like this:

The next step is to get a Google Analytics tracking code. To do this, you need to log into Google's Analytics page and from your main dashboard select "Add new Profile". As directed by the Google readme, create a fake domain for your project, like this:

The next page will give provide you with your UA-code.
To use Google Analytics with your Mobile App, just insert some code like this:
// Replace UA-0000000-1 with the code you obtained from Google:
string tracking_code = "UA-0000000-1";
int time = 10;
var tracker = GoogleAnalytics.GANTracker.SharedTracker;
tracker.StartTracker (account, time, null);
var label = new UILabel (new RectangleF (10, 10, 300, 20));
NSError error;
if (tracker.TrackPageView ("/app_entry_point", out error))
label.Text = "Tracking successfully sent!";
else
label.Text = "Error starting tracker";
// Force the event to be sent
tracker.Dispatch ();
And now your application is ready. Hit Run, and you should be tracking the use of your application.