I used one bridge and added all the VLAN’s to it. On the bridge VLAN you can add all VLAN’s and mark all ether ports either tagged (in case of a trunk port with multiple VLAN’s) or untagged (for a sngle VLAN or access port).
Please check this site: http://forum.mikrotik.com/t/using-routeros-to-vlan-your-network/126489/1