I use the Manything app and have done now for probably 5-6 months, I would highly recommend.
I have my Ipad or Ipod set up at home with the app on record and then check on them via the app on my phone or on the work PC.
It's free if you just need to check on them or £2.99 if you want to record movements and then look back, I did this for a while but don't bother anymore.
I have an Amcrest ProHD 1080P IP camera. It's both motion and noise activated; you can record and store onto an optional Cloud service or disk. Also, the helpline people in both USA and UK were brilliant and remotely took over my laptop to set it up for me when I was struggling with the technology.