Can someone help me convert a dotNet statement to a objective-C statement?

I am not a dotNet developer and was trying to read up some documentation on the following method:

signDate = Convert.ToDateTime("6/22/2011 8:35:21 PM");

What would be an equivalent function/method in objective C?

I am also not a .NET developer, but it looks like you're looking for dateWithNaturalLanguageString:

NSDate *signDate = [NSDate dateWithNaturalLanguageString:@"6/22/2011 8:35:21 PM"];

I believe you should check out the NSDateFormatter Documentation. In particular, I believe you want the method dateFromString:

In addition, or for a quick overview, check out the Date Formatters Guide.