Hyundai used the same factory keyless entry system on Sonata cars for the 2006, 2007, 2008 and 2009 model years. This system uses a 4-button keyfob-style remote transmitter with FCC ID OSLOKA-310T. The current Hyundai part number is 95430-3K202. Remotes Unlimited sells this remote as our part number 706-1706.
See 2006-2009 Sonata remote at this link.
This Hyundai factory keyless entry system requires a scan tool for programming, so you will have to take your vehicle and all remotes you plan to use with it to a dealership or qualified locksmith for programming.