string manipulation and methods in obj-c

I am very new to obj-c (about 1 day) and i have read the documentation on how to call methods and how to modify strings and i have used similar code in another program and it worked fine. I'm programming a simple web browser for the iphone to teach myself about WebViewController library. When i compile this it gives me the warning "'WebViewController' may not respond to '-parseURl:" at line 17 in the .m file and when i run it i throws the error "NSInvalidArgumentException" in the console.

Code for this in WebViewController.h:

#import <UIKit/UIKit.h>


@interface WebViewController : UIViewController {

    IBOutlet UIWebView *webView;
    IBOutlet UITextField *textField;
}

NSString *urlAddress;
NSURL *url;
NSURLRequest *requestObj;

- (IBAction)gotoAddress:(id)sender;
- (NSString*) parseURL:(NSString*)str;

@property (nonatomic, retain) UIWebView *webView;

@end

Code for this in WebViewController.m:

#import "WebViewController.h"


@implementation WebViewController

@synthesize webView;
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- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        // Initialization code
    }
    return self;
}

- (IBAction)gotoAddress:(id)sender {
    urlAddress = textField.text;
    urlAddress = [self parseURl:urlAddress];
    url = [NSURL URLWithString:urlAddress];
    requestObj = [NSURLRequest requestWithURL:url];
    [webView loadRequest:requestObj];
    NSLog(@"urlAddress= %s", [urlAddress cStringUsingEncoding:1]);
}


- (NSString*) parseURL:(NSString*)str {
    NSLog(@"made it");
    NSString *httpPart = @"http://";
    if ([str rangeOfString:httpPart].location == NSNotFound) {
        NSString *correctURL = [NSString stringWithFormat:@"%@%@", httpPart, str];
        return correctURL;
    }
    else {
        return str;
    }
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning]; // Releases the view if it doesn't have a superview
    // Release anything that's not essential, such as cached data
}


- (void)dealloc {
    [webView release];
    [super dealloc];
}


@end

Thanks for the help

Objective-C (and most other languages) is case-sensitive. "URL" and "URl" are different.

urlAddress = [self parseURl:urlAddress];

should be

urlAddress = [self parseURL:urlAddress];