I use the default mail program on Android Honey Comb. Today someone sent me an email with an attachment and there was no way to view it. Turns out you need an application to view your email attachments on Android devices.
Gmail Attachment Download allows you to save email attachments to your internal memory or to your SD card. Installing this app does not put an icon on your home screen; it works as a plugin for the email client. When viewing an email press the view or preview button in that attachment. You’ll then be presented with the options of where to download that file.
This app works for any file extension, you can download mp3 files or executable files. By default if someone attaches a text file there’s an option to preview the file, but you can’t download it to memory.
I think it’s pretty silly that an Android can’t do this by default without the assistance of third party software. Especially for tablet editions of Android which come with office and image editing software by default. Polaris office comes with the options to open up Word, XLS, and many other file types, so there’s definitely no reason to not allow you to download attachments.