Mitch Milam's Dynamics CRM and xRM Discussions

The labels for data entry fields on CRM 3.0 forms can normally only be set to the following values: Normal, Hidden, or Disabled.  Not a whole lot of functionality there should you wish to get inventive ( or at least, more descriptive ) with your forms.

Using a bit of JavaScript in the Form's OnLoad event, you can alter the labels in a variety of ways.

Changing the Weight of the font ( how dark it is ): 

crmForm.all.[field name]_c.style.fontWeight = 'bold';

Possible values:

normal, bold, bolder, lighter, 100, 200, 300, 400, 500, 600, 700, 800, 900

Changing the Font Style: 

crmForm.all.[field name]_c.style.fontStyle = 'italic';

Possible Values:

normal, italic, oblique

Changing the Background Color: 

crmForm.all.[field name]_c.style.backgroundColor = 'green';

Possible Values:

Named or value color

Changing the Font Color: 

crmForm.all.[field name]_c.style.color = 'green';

Possible Values:

Named or value color

Other style elements do exist, but to keep in mind that your changes do not need to vary the CRM user experience too much.

References:

Javascript style attributes

Hiding a Form Field Label in MSCRM 3.0

CRM 3.0 UI Style Guide