Reporting Procedure Where Clause Help (Multiselect)

When I've had to do the same thing, I just add this to the top of the proc:

declare @CSQList table (CSQID int)
while charindex(',',@CSQs) > 0
begin
 insert into @CSQList (CSQID) values(left(@CSQs,charindex(',',@CSQs)-1))
 set @CSQs = right(@CSQs,len(@CSQs)-charindex(',',@CSQs))
end
 insert into @CSQList (CSQID) values(@CSQs)

And then:

where CSQ in (Select * from @CSQList)

Works a treat.