Objective Charts is a wrapper library for the Google Charts API. While not fully functional (there is a lot you can do with Google’s Charts API), it can do quite a bit. Read the tests for further information on how to use it.
Just instantiate a GoogleChart object and start adding data, labels, legend, scaling, etc to the chart. Here is a short example:
#import "GoogleChart.h"
GoogleChart *chart = [[GoogleChart alloc] init];
chart.width = 320;
chart.height = 480;
chart.type = @"Line";
[chart.data addObject:[NSArray arrayWithObjects:@"1", @"2", @"10", @"100", @"500", nil];
// [chart url] ==> http://chart.apis.google.com/chart?cht=lc&chs=320x480&chd=t:1,2,10,100,400&chds=0,420
Objective Charts is released under an MIT-style license. See the ‘LICENSE’ file.