Wammu (Click To install)
It works with any phone that Gammu supports, including many models from Nokia, Siemens, and Alcatel. It has complete support (read, edit, delete, copy) for contacts, todo, and calendar. It can read, save, and send SMS. It includes an SMS composer for multi-part SMS messages, and it can display SMS messages that include pictures. Currently, only text and predefined bitmaps or sounds can be edited in the SMS composer. It can export messages to an IMAP4 server (or other email storage).
It cannot browse the files on a phone.For that you can use gMobileMedia.
gMobileMedia (Click To Install)
A short description this application let's you easily upload and download images, ringtones, photos and applications to your mobile phone, all that you need is a data cable or any other connection method supported by gammu.
This application has been targeted mainly for Nokia cell phones (I only have those to test), but theoretically it can handle all the phones that gammu has support for. This is also because I never could found an easy to use alternative in Linux for Nokia's PC Suite.