for my razr maxx, I use winamp on my computer to create playlists. Once you create a .m3u playlist, you can transfer the .m3u playlist file and all music files to your droid phone. Then Winamp App or Google Music App can read the .m3u playlists and play the corresponding music files.
I haven't used any other music Apps but they probably can read the .m3u playlists since it's a standard/common format...for now.
In summary, create a playlist using a .m3u file with whatever music software you have, transfer the playlist file and music files to your phone, and then you should be able to play your music by choosing these playlists.
This is the easest method i know.
and an extra helpful note is you can change the .m3u file extensions to .txt and open it using a Word Doc Program such as notepad, MS Word, WordPad, ... and can edit filenames and addresses in the playlist. This is useful because if you copy/transfer music from computer to computer, or use an external hard drive for music and the Drive Letter changes, you can open the .m3u file and perform a find/replace for all of the hard drive letters (for instance, find C:\ and replace to D:\) so that you can use the playlist for accessing files on a hard drive with a different letter assignment.
Hope this helps.
RamblinRoyce
Edit...
Also, you don't have to worry about the playlist files and addresses on your phone. In other words, the music file paths & folders on your phone don't have to match the file paths & folders on your computer. Android indexes and can find the music file in your playlist (based on the filename I'm assuming) and the music file can be in any directory or any folder. If the music player app is having problems finding music files, power off and power on your phone... i believe android indexes the files every time it boots up so if you add new files, your music app may not know the files exist until you restart the app and/or restart the phone.