1600M, 2424M, 4000M, and 8000M
See the "Network Monitoring Port Features" section of chapter 6 of the HP ProCurve Switches 1600M, 2424M, 4000M, and 8000M Management and Configuration Guide.
See the "Port Monitoring Features" section of chapter 10 of the HP ProCurve series 2500 switches management and configuration guide.
Mirroring is enabled using the "Ports / port mirroring" page of the web interface, and seems to work perfectly. At the time of writing (Oct 2007) this seems to be a particularly good value switch for this purpose, costing much less than many of the alternatives.
New ProCurve switch (introduced in 2009?) that is gigabit on all ports and supports port mirror. This switch is somewhat similar to the 1700-8 and is also relatively low cost. Unlike on the 1700-8, the mirror destination port will not function as a normal port; this may necessitate a second Ethernet connection to the computer running Wireshark. There is also an older version, the 1800-8G, that this switch replaces.
GbE Switches 6400, 5300, and 3400
See the "Interface Monitoring Features" section starting on B-23 (page 477) of the HP ProCurve Switches 6400, 5300, and 3400 Management and Configuration Guide.