Cannot convert from system...IList to class[]

[C# Programming]

Please could somebody help... My brains gone dead http://www.barakasoft.com/script/Forums/Images/smiley_doh.gif

I'm trying to pass the following to a wcf service
public IList GetItemsWhereIn (IList iclass)
{
iServiceClient svc = new iServiceClient();
IList list = svc.FindItems(iclass);

return list;
}
The problem is passing parameter iclass to svc.FindItems
error Cannot convert from system...IList to tbClass[]

The wcf service is setup as
public interface iService{
[OperationContract]
List FindItems(IList iclass);}
And the linq query as
public List FindItems(IList iclass)
{
...linq code working correctly
}
If you could point the way I would be very greatful http://www.barakasoft.com/script/Forums/Images/smiley_biggrin.gif