After a bit of researching, I found this:
Payments for successfully processed
orders are sent for disbursal to your
account within two business days.
However, the actual payout for your
Google Checkout account will be
initiated as per the applicable payout
schedule for your account. Once the
payout is disbursed to the bank
account you have verified, depending
on the region, your bank will make
those funds available to you as
defined by their policies. To learn
more about your bank's turnaround time
for electronically deposited funds,
please contact your banks'
representative.
If I'm reading this correctly, it seems that your Google Checkout account is credited with purchases (70% of the application's Market cost) within two days, but your bank account is actually credited based on "the applicable payout schedule for your account." What that is, I do not know. Maybe an actual Android developer can shed some light on that. But it appears that, like Apple, you get "lump sums" (probably once a month or so, but I'm not sure).