public with sharing class lead_create {
public lead_create(){
set<id> lead_l=new set<id>();
lead_l=[select id from lead where rating like:'%hot%'];
task t=new task(subject='email',whoid=lead_l.id);
insert t;
}
}

Error: Illegal assignment from List<Lead> to Set<Id> at line 4 column 1

Please help!!
Thanks in advance

How do I share an account record (and associated contacts), so that it is available to external customer community users? The account record will be owned by an Internal user. 

This is basically for a VF page in my customer community where there is a contact lookup field. The external users have to select contacts accociated with a particular account "ABC" only. I have put in a lookup filter, but it is only working for the internal users. The external users are not able to see anything, most probably because they do not have access to he "ABC" account record. Please help!!!