[plt-scheme] scheme equivelent(?) to select(2)?

I'm working on the tcp portion of my server monitor.  I C at
this point I would use select(2) to detect if any connections to
servers had messages to read. In the manual under the TCP section
I do see ways to 'peek' for bytes, but nothing that seems to be a
select() call. I have my connections stored in a hash and am using
(hash-table-for-each) to loop through the current connections. I
guess what I really want is more of something like (read? p) that
returns #t if there are bytes available for reading.

Mike