Passing A List/array To An SQL Server Stored Procedure 2005

Hi, I m using sql 2005 as a back end in my application...

I am useing Store procedure..for my data in grid..

 

ALTER PROCEDURE [dbo].[ProductZoneSearct]

(

@Productid char(8),
@Proname char(8),
@radius int,
@mode varchar(5) = 'M',
@Zone nvarchar(1000),

)

AS
SET NOCOUNT ON;
Create Table #Product (ProductID int, TimeEntered datetime, DateAvailable datetime, Productname varchar(80), City varchar(50), State char(4),Miles decimal, Payment varchar(40),UserID int, Phone varchar(15))


Insert #Product
Select ProductID , TimeEntered, DateAvailable, Productname ,City,State,miles,Payment
,Miles, UserID, Daily, Phone
From [tblproduct]
Where city IN (@Zone)


Select ProductID TimeEntered, DateAvailable, Productname City,State,miles,Payment
,Miles, U.Phone As phoneNumber, Company, , L.Phone As cmpPhone
 From #Product As L
 Left Join (Select UserID, Company, Phone, From [User]) As U On U.UserID = L.UserID
  Order By DateAvailable

 

if i pass value in "where city in (@Zone)" and @Zone ='CA','AD','MH'  then it can not get any result..but if write where city in ('CA','AD','MH') then it give me perfact result..

I tried to below syntax also but in no any user
Where city IN ('+@Zone+')

In short if i pass value through varibale (@Zone) then i cant get result...but if i put  direct value in query then only getting result..can anybody tell me what is problem ?

Please Hel[p me !!!

Thank you !!!