need regex help

[xuron]

I have lines that look like this

12345678:firstname

ID:Name

What is the regex code for deleting everything after the ":"

This is what I have so far, but its not getting all the characters

:[a-z\s]*$

[Dvae]

Try
.*?\w+)\s*$

[calmlikeabomb]

$item='12345678:firstname';

$parts=explode(':', $item);

//Outputs

$parts[0]='12345678';
$parts[1]='firstname';