To use any of these email based file conversion services, just send your files (like DOCX, PDF, MP3, etc) as email attachments to the address of the conversion service and theyll send back files in converted formats almost instantly. firstname.lastname@example.org - Convert WAV to MP3 format email@example.com - Convert DOC, XLS or PPT files to PDF firstname.lastname@example.org - Convert PDF to Word or RTF You can use the Koolwire email conversion service to convert files as large as 10 MB. email@example.com - Send an email with the URL of the web page in the Subject field (e.g. www.bigjugs.com) and youll soon find a copy of that web page in your Inbox. iPhone@pdfonline.com - Convert Microsoft Visio (VSD) and Word 2007 (DOCX) to PDF. You can send multiple file formats in the same email and the converted PDF documents will arrive in separate emails.