No personal exprience, but there's quite a bit of discussion at the
HRPC site (http://groups.yahoo.com/), then hrpc group. Here is an
excerp from one discussion, but you I'd recommend joining the group
(requires submitting a medical digest, but it's worth it).

regarding Avastin. The dose and schedule varies by type of cancer
it is used against. Lung, Breast and Colon have their schedules. Since
prostate cancer use isn't FDA approved yet (phase III in progress) the
best
data available is from phase II trials -- I found 2 -- one with
emcyt/docetaxel/avastin and one with docetaxel/thalidomide/avastin --
both
every 3 weeks for both the avastin and docetaxel. Here's the
references:

J. Picus, S. Halabi, B. Rini, N. Vogelzang, Y. Whang, E. Kaplan, W.
Kelly,
E. Small; The use of bevacizumab (B) with docetaxel (D) and
estramustine (E)
in hormone refractory prostate cancer (HRPC): Initial results of CALGB
90006; ASCO 2003, Abstract No: 1578.

Rich