Always, always you should use a different VLAN than 1, even if you are not planning to do anything clever. Simply create another VLAN and assign all your ports to this VLAN:
vtp mode transparent !always use this
!
vlan 10
name Data-VLAN
!
vlan 100
name Voice-VLAN
!
interface range FastEthernet0/1 - 48
switchport mode access
switchport access vlan 10
switchport voice vlan 100
!
You will need IP connectivity (routing) between your Voice & Data VLANs if your DHCP server is going to be on VLAN 100 and your access ports in VLAN 10 (or VLAN 1 if you don't follow my advice). There are various options for achieving this but since I don't know your topology apart from 1 Cisco 3560 & 1 Dell switch it's a bit difficult to advise you.
Even though this sounds like a simple setup I would advise you to design it properly, as I would with any network implementation.
HTH
Andy