You need to set the minimum font size for the TextLabel.
UILabel Class Reference
adjustsFontSizeToFitWidth
A Boolean value indicating whether the
font size should be reduced in order
to fit the title string into the
label’s bounding rectangle.
@property(nonatomic) BOOL
adjustsFontSizeToFitWidth
Discussion
Normally, the label text is drawn with
the font you specify in the font
property. If this property is set to
YES, however, and the text in the text
property exceeds the label’s bounding
rectangle, the receiver starts
reducing the font size until the
string fits or the minimum font size
is reached.
The default value for this property is
NO. If you change it to YES, you
should also set an appropriate minimum
font size by modifying the
minimumFontSize property. Availability
* Available in iPhone OS 2.0 and later.
See Also
* @property font
* @property minimumFontSize