Ever since getting my smart phone a year ago I've been using the handy Ravulous app for android. It's a quick and easy way to upload photos, update WIPs and check my queue when I'm out and about. As we all know, there's nothing worse than standing in a yarn shop ready to purchase, only to realise that you can't remember what weight of yarn you need, or how many skeins. In fact, it's so handy that I definitely wouldn't be without it now.
It has become a lot more useful now though with the recent addition of a simple row counter app.
Called County Plus it can be downloaded from Google Play and it can be made to synch with your Ravelry account. You can upload your current projects to it and then use the counter to keep track of your number of rows. You can also have more than 1 counter per project - enabling you to keep track of raglan increases and a lace pattern at the same time, for example.
As knitting apps go, it is at the simpler end of the spectrum but jolly useful - and it is a firm favourite on my phone.