gMobileMedia let's you upload and download images, ringtones, photos and applications to your mobile phone, it uses gammu as its backend. gMobileMedia is a simple gtk application used to browse and handle a mobile phone filesystem, it can handle phones with more than one memory area (thanks to gammu). This application is released under the GNU/GPL so you are freely able to change it, modify it and redistribute it as long as you keep your work under the same license.
This application has been targeted mainly for Nokia cell phones (I only have those to test), but theorically 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.