How to combine two regular expressions

Hi Everyone,
I don't have much experience with regular expressions and I was wondering if someone could help me.
Basically, I have a textbox which I want to be restricted to 8 numeric digits.  I think what I want is a combination of these two simple regular expressions but I don't know how to "OR" them together.  The two would be:
[0 - 9]{1,8}
"OR'd" (so to speak) with
0+
In other words I want the input to be up to 8 numeric digits with the exception of a series of zero's of one or more.  For example, these input patterns would not be allowed:  "0", "00", "000" . . . "00000000".  You get the idea. 
Can someone help me combine the two expressions above into one regular expression?
 
Thanks,
Pete