Here are three useful printing apps for your iPhone or iPad. 1. HP ePrint. "The HP ePrint App makes printing from your iPhone, iPad or iPod Touch easy, whether you are at home, in the office, or on the go. Features: • Print from your phone over Wi-Fi, via the Internet to an HP ePrint printer, or directly to HP wireless direct supported printers.   • Print to convenient HP Public Print Locations, like print/copy stores, hotels, and airport lounges.   • Supports HP ePrint Enterprise (service and internet purchased separately). For more information, check http://www.hp.com/go/eprintenterprise  Select and print photos and content from the cloud via Evernote, Box.net, Dropbox, and more, as well as via your email and the web. Supports most major file types (Microsoft Office documents, web pages, email attachments, photos, PDF and text files)."
2. Epson iPrint "Print anytime and anywhere to Epson printers from your iPhone, iPod Touch or iPad. Print photos, webpages and files including Microsoft® Word, Excel®, PowerPoint® and PDF documents. You can even scan, save and share your files. Also supports online file services such as Box, Dropbox, Evernote® *1. Epson iPrint makes printing easy and convenient. Print directly to a wide variety of Epson printers within your wireless network. Key Features • Print, scan, and share directly from your iPhone, iPod Touch or iPad • Print from anywhere in the world with select printers using remote print functionality • Print photos, PDFs and Microsoft Office documents such as Word, Excel and PowerPoint • Print your email attachments and stored files • Access and print your online files from Box, Dropbox and Evernote. • Use the built-in web browser to find the webpage you want to print • Configure your print options including paper size and type, number of copies, page range and one- or two-sided printing • Scan from your Epson all-in-one and share your file (save to your device, send via email or save online) • Check your printer’s status and ink levels • Get help with a built-in FAQ section • Supports iPad, iPad 2, iPhone 3GS, iPhone 4, iPhone 4S and iPod touch (3rd generation and later) Advanced Features • Choose and print multiple photos • Print with and without borders • Switch between color or monochrome printing • Choose from different scanning resolutions and image types • Optimize print quality • Buy ink and supplies for your printer • Setup & register to Epson Connect"
3. AirSharing "—FEATURES— Create a wireless hard disk View documents Many file formats supported Email documents Connect to your computer Mount remote file servers Perform advanced file operations Print documents Share files with other users —FEATURE DETAILS— CREATE A WIRELESS HARD DISK Mount your iPhone or iPod touch as a wireless drive on a Mac, Windows, or Linux computer (on the same Wi-Fi network), or connect from any web browser Drag-drop files between your computer and Air Sharing Pro Host a powerful web server with WebDAV (just like the iDisk) No special software required on your computer (except on Windows XP, which requires free NetDrive app) Security: local passcode, remote access password, optional Public folder VIEW DOCUMENTS Scrollbar for fast access in large documents Folder popup for jumping back to previously viewed folders Advanced auto-detection of text-file character encoding, using linguistic analysis PDF Table of Contents for easy navigation PDF page thumbnails PDF Go To Page High-quality viewing of large images Slide show Save images to Photos Bookmarks MANY FILE FORMATS SUPPORTED iWork (Pages, Numbers, Keynote) Microsoft Office (Word, Excel, PowerPoint), subject to iOS compatibility Web Archive (web pages downloaded by Safari) HTML web page PDF (even password-protected and large documents) Adobe Illustrator (saved as PDF Compatible) RTF (Rich Text Format) and RTFD (with embedded images) Plain text (many character encodings) Source code (most popular programming and scripting languages), with color-coded formatting Movies, Audio, and Images (standard iPhone formats) CONNECT TO YOUR COMPUTER Mac OS X: just turn on Remote Login Linux: enable SSH Windows: download free Core FTP desktop app Mac OS X found automatically via Bonjour MOUNT REMOTE FILE SERVERS Dropbox Box.net Google Docs iKeepInCloud Storegate FilesAnywhere (WebAdvanced), MyDisk.se, CloudMe, other WebDAV servers Secure HTTPS connection when available FTP SSH (SFTP) View documents directly (automatic local cache) PERFORM FILE OPERATIONS Move, Copy, Paste, Rename, Delete, New Folder Zip and Unzip (supports password-protected archives) Print (via Mac OS X 10.5+ or Linux with Printer Sharing) Email attachments Save and Get images to and from Photos Download from URL (copy link from Safari, paste into Air Sharing Pro) PRINT DOCUMENTS Requires Mac OS X (10.5+) or Linux with Printer Sharing Prints most viewable formats No special desktop software required SHARE FILES WITH OTHER USERS Auto-detects other users on same Wi-Fi network Connects to Air Sharing or Air Sharing Pro on another device"
For more, see the original article at the link below.