With people even more obsessed with clouds today than William Wordsworth was back in the 1800s, it makes sense that network attached storage (NAS) box manufacturers are keen to jump on the bandwagon.However, it's all well and good calling something a "personal cloud", but if that only works when you're at home, or via a complex process of port forwarding and fixed IP address assignment, then it's no substitute for the consumer-friendly external solutions, such as Dropbox.That's why Western Digital has an iPad and iPhone application that makes accessing its NAS\/personal cloud drives, both locally and remotely, a piece of cake...WD 2go Pro\nFormat\niPad (version tested) \/ iPhone \/ iPod touch\nPrice\n\u00a31.99\nWhere\niTunes\nDesigned specifically to work with Western Digital's My Book Live and My Book Live Duo network storage drives, WD 2go Pro is an expanded version of WD 2go, which is available free on iTunes. However, the extra features offered by the paid version are well worth the nigh-on two quid extra.Both applications allow you to access your compatible NAS box(es) either locally or via an internet connection, and both offer the ability to look at documents, pictures, video and music stored thereon using a variety of iDevices - but only the Pro version will let you download copies of your files for offline viewing.You will also need the Pro version if you want to email files, either directly or with a web link, print them through AirPrint, or open them up in an external application.The first thing you need to do before sparking up the app is to assign each WD My Book Live with a 4-digit access code. Then enter it into the app and bingo, no matter where you are you'll see your own "personal cloud" pop up in the side menu. You can then browse through it to your heart's content, and open up any stored files.Well, we say "any" files, but thanks to the limitation of the iPad (or iPhone) itself, you can only access those that are compatible.For example, video playback is restricted to\u00a0MOV, MP4 and M4V file types. It won't play AVI, MKV or MPG videos as the device doesn't naturally do so. Nor can you send those files to a third-party app that will play them - they just won't work at all.Most music files we tried worked, including MP3s and M4As, and the same went for picture formats and documents. PDFs were even supported naturally, and it\u00a0became an ideal way to read converted comic books remotely.The offline feature works simply too, all you have to do is click the clip symbol at the top of the menu box and then clip whatever files you would like to make available. Bigger files will take a while to download, especially if you're accessing the system remotely - and you do need the right amount of spare internal storage - but it's great if you're about to travel in a plane, for instance.The final stand-out feature is the ability to email content to yourself or another. It is restricted in filesize for actual attachments, but we managed to send a link to a full HD movie, which then started to download when we clicked on it in the received email (all 1.9GB of it).OK, so WD 2go Pro is not for everyone - you have to have a Western Digital network drive for starters - but we find it very useful, for work and play and especially when on our travels. It'd be better if we could also upload files to the drive(s) through the app, and would hope WD looks into that for the future.