I just moved from Eagle to Altium. I cannot find SMD resistors in Altium libraries. In Eagle, there are almost all general components. In Altium there are only few resistors. Where can I download the libraries? Or, do I need to make my own for every component I use?
Altium 13 features Vaults as a primary means of managing your components. You will need to setup a connection to Altium's Hobart Vault (something like public repository) to access the components. Generic SMD resistors can be found e.g. under Components - Generic \ Resistors \ Basic Surface Mount.
I believe there is a library named Standards.IntLib. You might find SMD components there. Also the components you have on your schematic, go to properties and check if SMD Footprint is available for that component. If not you can make your own SMD footprints which are very easy to make. Let me know if you need any help with that.
When I last used Altium/Protel, integrated libraries were just being introduced - I used separate schematic and PCB libraries, and, as I recall, the PCB footprint library had many SMD footprints - for resistors and capacitors, they were named by their US size designation: 1206, 0805, and so on. On the schematic for resistors I used "RES" from devices.lib. I would manually assign the appropriate footprint.