Go thru these Testcases, if any more to add or any of them 
to be correct ,plz do it...

Check for the availability of the Mobile
Check the buttons on the mobile
Check the mobile is locked or unlocked
Check for the  unlock of the mobile 
Select the menu
Check for the messages in menu
Select the messages
Check for the write message in messages menu
Select the write message
Check the buttons writing alphabets
Check for the  chars  how many u can send
Write the message on the write message menu
Select the options
Select the send
Check whether asking for the phone No. of the receiver
Select the Search for the receiver Phone No.  if Exits
Enter the Phone No. of the receiver
Select Ok
Check for the request send 


Thanks

Latha, u juss specified positive flow.

main scenarios are:
1. Check whether u are able to send if Entered Text exceeds 
the limit
2. Try to send the message to invalid number(Less than 10 
digits and the number doesnt exist like 1111122222)

3. Try to send a message to ur mobile 

Please do concentrate more invalid validations instead of 
+ve flow.

In addition to that u can also test

1. check whether u r able to send to many.
2.check whether u r able to send to any mobile which is 
temporarly disconnected.
3.check whether u can send to landline no,toll-free no.

Hi mese how are u? I am fine Ur phone is not give the 
answer so please read the message and send the document

first u can check the battey life. if battery life is gud u 
can proceed

Hey, First of all to test before any product 
;- test its basic functioanlity like
1. Where message option is present in mobile.
2. if yes then does it open after pressing the select button.
3. check how much options are there , there should be
atleast inbox, create, draft and sent.
4. Click on Create , does it open text box.
5. does it allow user to write.
6. max. character length. 
7. enter number to which u want to send. does it accepts.
8. click on send button, does it send the message.
there are many more scenarios which we have to test but
after testing the basic functionality positive flow if it
works then we should go ahead for negative testing.