+2  A: 
myLabel.numberOfLines = 2;

Check the docs for full info on how to use this property.

Rob Napier
the problem is that it won't always be a specific number, it will change for each row
Jason
The numberOfLines property sets the **maximum** number of lines. Set it to a high value. (And, as Rob said, check the docs.)
Nikolai Ruhe
You also have to set the myLabel.lineBrakeMode to UILineBreakModeWordWrap.
Nikolai Ruhe
Setting it to 0 means "no maximum." @Nikolai's right about lineBreakMode; I had in my head that WordWrap was the default for UILabel, but it's not.
Rob Napier
+5  A: 
notnoop
This is great. Thanks.
z s
+1  A: 
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    return theSizeYouWantYourCellToBe;
}
MrThys