MultiSelect field doesnt give Item Names but only system ID. How can I get Item Names of selected items from a multi select items

MultiSelect field doesnt give Item Names but only system ID. How can I get Item Names of selected items from a multi select items

Basically I want item names from lookup based multiselect field.
I have a lookup in which I have selected a multiselect field, and when I select items in multiselect and submit the  buttons , I only get System Id.  I have written following code on submit buttton- 

<some variable> = input.<multiselectfield>

I have even tried fetching Item names using for loop with following code but and I succeeded in getting name but it only returns 1 same name even if I select another item name :
 
for each input in input.multiselectfield
{
    tempvar=  <another formname> [ID == input.multiselectfield];
    input.somefield = input.somefield + tempvar.ItemName.toString();
}

it only returns 1 same name even if I select another item name .

pls help me in fetching names from lookup based multiselect items ..

Thanks...

Vaibhav.