An error occurred while accessing ‘My_flash’, the system responded: org.freedesktop.Hal.Device.PermissionDeniedByPolicy: org.freedesktop.hal.storage.mount-removable no <– (action, result)
or

Could not mount the following device:
My_flash

Solution:
add to PolicyKit config file(/usr/local/etc/PolicyKit/PolicyKit.conf) your user:

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE pkconfig PUBLIC "-//freedesktop//DTD PolicyKit Configuration
1.0//EN"
"http://hal.freedesktop.org/releases/PolicyKit/1.0/config.dtd">

<!-- See the manual page PolicyKit.conf(5) for file format -->

<config version="0.1">
<match user="root">
<return result="yes"/>
</match>
<define_admin_auth group="wheel"/>
<!-- You should add the following strings -->
<match action="org.freedesktop.hal.storage.mount-removable">
<match user="slim">
<return result="yes"/>
</match>
</match>

</config>

where slim – your user.
and finally restart hald:
howtobsd#/usr/local/etc/rc.d/hald restart

hostobsd#pciconf -lv |grep Wireless
device = 'Intel 3945ABG Wireless LAN controller (10208086)'

find device in Hardware Notes:

[i386, amd64] Intel PRO/Wireless 3945ABG MiniPCI network adapters ( wpi(4) driver)

So, wpi is driver for my wi-fi device.

Following the instruction wpi(4), going to configure the kernel with options:
device wpi
device wpifw
device pci
device wlan
device wlan_amrr
device firmware

You also can load driver without kernel configuring by adding in /boot/loader.conf
if_wpi_load=”YES”

add in  /etc/rc.conf:
wlans_wpi0=wlan0
ifconfig_wlan0=”WPA DHCP”

create configuration file for our wireless connection :
howtobsd#touch /etc/wpa_supplicant.conf
howtobsd#vim /etc/wpa_supplicant.conf

and add there ssid and password(for WPA-PSK):
network={
ssid=”yourssid”
psk=”yourspass”
}

and finally reboot

snd_driver is driver, that include itself supporting the most popular sound card drivers.

But I think better to install kernel with support exactly yours sound card. For this way we have to identify device model:
slim# pciconf -lv | grep audio
device = 'Intel audio controller embedded with the 82801H chipset ( ICH8 chipset ) (82801H)'

find this sound card in the Hardware Notes :

and make kernel with options:

device sound
device snd_hda

You also can load driver without configuring kernel. Add in /boot/loader.conf:
snd_hda_load=”YES”