How to group query by x unit

Hi,

I'm using this little query :

SELECT Sum(PageCount) as NbPage, UserLogon FROM AuditTrail
where CostCentreName = 'Etudiant'
and Timestamp >= convert(datetime, '2011/04/13')
group by UserLogon order by NbPage desc

Select allOpen in new window

It show's me how page is printed by user. My SQL is quite old and I can't remember how to "summarize" those data.

I want to know how many users have for exemple :
1 to 500 copies
501 to 1000 copies

etc...

Thx for help.