Smart phones are ubiquitous these days and they've become a useful tool for roving (beer) drinkers. Not least having Google Maps to hand can help prevent walking in the opposite direction to where the pub is! I've assembled a collection of apps I use regularly below, no doubt people will be aware of some, but hopefully there will be others that come in handy.
Finding decent beer is often a challenge, especially when in unfamiliar territory. the first three apps are all beer finders of one sort or another.
Good Beer Guide is the venerable CAMRA publication now available in app form. It allows you to locate nearby pubs and "tick" pubs if that's your thing alongside all the content from the printed book in a much more travel-friendly format. Charges a small annual fee.
Craft Beer London is an app from journalist Will Hawkes covering decent beer bars, pubs and breweries all over London. One off purchase price.
Beoir Finder is a free app to find Irish Craft Beer all over the island of Ireland. Regularly updated (full disclosure: I'm a Beoir member)
For those whom reviewing and cataloguing beers consumed is a force of habit, both Ratebeer and Untappd have mobile apps.
Untappd (from repatriated Bristolian Lee Williams) allows check-ins via foursquare and awards to collect, whilst the Ratebeer app (designed by site user Eric Kok) is a great catalogue of beer information, allows offline rating and also has a places finder.
Aside from beer apps, there are some great apps for keeping up with beer news, or getting yourself organised whilst on a day out.
Train Times UK is indispensable for planning train journeys and checking current status of trains. You can find out whether you've time for another before heading to the station...
One off purchase price
One off purchase price
RSS Demon is what I use as a blog aggregator, add whatever you want to read on there and posts autosync to your phone. Great for long bus journeys.
Pocket is another handy little app to bookmark and cache long articles/ blog posts for later reference. Thanks to Boak and Bailey for mentioning this one!
Dropbox is a great way of transferring files between phone and computer or vice versa. It saves having to use a USB lead to transfer those snaps captured whilst on the go.
Feel free to suggest other apps people should be using in the comments below.