For iOS7 or more you can use this:
NSString * htmlString = @"<html><body> Some html string </body></html>";
NSAttributedString * attrStr =
[[NSAttributedString alloc] initWithData:[htmlString dataUsingEncoding:NSUnicodeStringEncoding]
options:@{NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType}
documentAttributes:nil error:nil];
UILabel * myLabel = [[UILabel alloc] init];
myLabel.attributedText = attrStr;