http://www.getharvest.com/
Expense reporting, time tracking and invoicing system. Starts from $12/mth for 1 user. $40/mth for 2-5 users. Pricey, but looks solid. Includes twitter based SMS/IM integration (neat). Feels quite ajaxy, nice design. Hat tip Jamie Cockburn.
http://www.myintervals.com/
Intervals is an online time tracking / invoicing system like FreshBooks / CashBoard. The web site seems dull. SSL is only available on $100/mth+ packages. $20/mth covers up to 10 projects, 500Mb, unlimited users.