Samsung Intensity II
1. and the easiest... just send song clips to yourself as an mms message... tons of ways to do this, you can get a cutter and make your own or there are plenty of sights. you can also cut the clips and put them on memory card then just mms them to yourself when you want one and then save as ringtone. if you are wanting someone to send you one they have just have them message it to you and you can save the file.
2. if you want full songs get a memory card
as far as unlocking bluetooth, it is not an issue of it being locked, the phone simply doesn't have those profiles
I remember a lawsuit when Verizon's first bt-capable phone came out, because of all the blocked capabilities.
Intensity BT profiles
Supported Profile: Headset, Handsfree, Stereo, Phonebook Access, Basic Imaging, Object Push for VCard & VCal, and Serial Port
Those are your profiles