how to split the substring in SQL server 2008

CREATE FUNCTION [Split]
	(
		@String varchar(8000),
		@Delimiter char(1)
	)     
	returns @temptable TABLE (items varchar(8000))     
	as     
	begin     
		declare @idx int     
		declare @slice varchar(8000)     
	    
		select @idx = 1     
			if len(@String)<1 or @String is null  return     
	    
		while @idx!= 0     
		begin     
			set @idx = charindex(@Delimiter,@String)     
			if @idx!=0     
				set @slice = left(@String,@idx - 1)     
			else     
				set @slice = @String     
			
			if(len(@slice)>0)
				insert into @temptable(Items) values(@slice)     
 
			set @String = right(@String,len(@String) - @idx)     
			if len(@String) = 0 break     
		end 
	return     
	end

SELECT * from Split('RET:WHO:IMP:XMP',':')