I've got two MP3 files from my friend via Gmail. How can I save them to my phone? There is only a Preview button...
Sounds like you have a crippled version of the app.
I emailed myself an mp3 file and got "Download" and "Preview" buttons. Pressing "Download" downloaded the file (as one would expect) to
(This is an original DROID with Froyo.)
After I installed the ASTRO file manager and I went to "Preview" - ASTRO popped up, and saying, "give a filename" ok, then it saved the files!! (the files must be ex.: zipped!!) - and then I was able to extract the files in the zip.
You can't, at least not with any consistency, and it looks like you can't request the feature anywhere either. You'll need to use a different email client, or wait for the Google Apps team to implement this out of the blue.
I found a number of apps just for this purpose:
All of these apps function by becoming options when you click on the Download or Preview button. These are just a couple that I tested out. Download All Files was my favorite. I'm sure there are other apps out there with similar functions.