New Element around the first Letter of a String

New Element around the first Letter of a String

Hi,

How can I create a new element around the first Letter of a dynamical outputted string? I need this because I want the first letter in another color.

Now:
<span class="boxTitle">Login</span>

Target:
<span class="boxTitle"><span class="firstLetter">L</span>ogin</span>

I am a jQuery noob, so which functions have I to use to reach the written target?

Thanks for helping,
Redfish