I might be very late to the party with this one. But I have recently realised that Transport for London/Oyster will email me a monthly journey statement for my tube travel.
Previously you had to go on and select the journey and print it off. They only keep 8 weeks worth and I always found myself missing out days/weeks where I left it too late to print it out. 
Now I receive a monthly email with all my journeys. V handy as they make up a lot of my expenses etc. And I can just file the email until I do my accounts.
As I say not sure how long the email facility has been on offer, but it was a revelation when I realised!
Thought I'd mention on here should it be of interest to any others.
www.tfl.gov.uk/tickets/20785.aspx
Journey history
Log in to your Oyster online account to see the journeys you've made using pay as you go, a Travelcard or a Bus & Tram Pass.
See all the journeys you have made right up to the end of the previous day. You can see up to eight weeks worth of journey history and select which week you want to view. Your journey history can be downloaded as a csv text file, which can be used with most spreadsheet/database applications.
You can also get your journey history emailed to you on a weekly or monthly basis.
You can only see your journey history from the day after you set up an Oyster online account.