If you have them stored as Google contacts, and have syncing of your contacts turned on, then logging into the same Google account on your SII will be enough: they'll just synch to the new phone.
Otherwise, the simplest is probably to go into the phonebook on the HTC, select "export" in the phonebook app's settings (should be there when in "People" view, i.e. when viewing the whole phonebook). This copies the contacts to a vcard file (.vcf) on the sd card. Copy that to the PC (so you have a backup), then copy to the new phone and "import" it into the phonebook of the new phone.