What application do you guys use for hourly client billing/tracking?
Probably a "stupid" question, but very useful for those just starting.
I really like Harvest - http://www.getharvest.com.
For smaller time-keeping where I'm not sending a formal invoice, I like "Desktop Task Timer", which I got through the Mac App Store.
I use Billings Pro (OS X only). It handles time tracking, invoicing, and reporting. The biggest benefit for me is the ability to design invoices, estimates and reports.
The 'Pro' version creates a server that other Billings Pro clients can sync to, great for a team environment. But watch out -- I've had very mixed results with clients that often change IP address -- such as laptops coming and going.
Billings - http://www.marketcircle.com/billings/
Billings Pro - http://www.marketcircle.com/billingspro/
There are also iPhone and iPad versions that will sync with your local installs (Billings) or your server (Billings Pro).