VirtualBox harddrive file (.vdi) seems never shrink, whatever I do in the guest windows. We can fix this. Following is taken from http://kakku.wordpress.com.
For the reference, disk space can be also managed by turning off indexing, logging, restoring, and virtual memory. Also windows have a one stop cleaning center, which can be accessed by right clicking on the disk drive in the explorer.exe.

We’ll need the following tools:
1. http://www.feyrer.de/g4u/nullfile-1.02.exe : This tool zeroes out free space, which our next tool compresses. For Linux based OS, search for a file, zerospace.c, which you’ll have to compile yourself.
2. VBoxManage : This tool is the command line management tool that ships with VirtualBox. Whatever you can do with the GUI, can be done by this. + A lot more

Ok now.

1. First boot into your VM. Defragment your drive atleast 2 times.
2. Copy the tool, nullfile mentioned above to the VM and run it. A simple double click should do it.
3. Now shutdown the guest. Open a terminal in the VM image directory. Most probably /home/_user_name_/.VirtualBox/VDI
4. Run our final command, We would be done after this.
VBoxManage modifyvdi _file_path_ compact
e.g. in my case I ran: VBoxManage modifyvdi /media/Blockk/VDI/NewHardDisk1.vdi compact

How to show all the USB devices dimmed in grey in VirtualBox

Grabbed this from here.
Basically, with setting up correct user group, all the dimmed devices come back to be ready. No.2 concerns iPhone and iPod Touch because it has a problem in connection in recovery mode.
For making VirtualBox work with iTunes, see this page.

1. Setup correct user group
Try this:
1. In the host (10.04 Lucid), System->Administration->Users and Groups
2. Click Manage Groups.
3. In the Groups settings List Box, navigate down to vboxusers
4. With vboxusers high lighted, click properties
5. Click the check box next to your user name to indicate you want you to be a member of the vboxusers group.
reboot the host.

2. Created a USB filter in VBOX, cleared all of the fields except for the "Vendor ID" field.

A driver and GUI for Nike+ Sportband

ps2.
Interesting enough, I tried VirtualBox with USB setting, and it works just fine. But the information was as comsport suggested, so there might be some relation anyway? I wonder, if I need the driver at all, and I think I can just put the information in VirtualBox usb setting by myself.

ps1.
I just found it doesn't run correctly. The error message:
username$ comsport -h
*** stack smashing detected ***: comsport terminated
Segmentation fault

Googled the error message, but I don't know what to do! Can this be a problem caused by checkinstall???
I found a candidate for the solution here:
"I have been dealing with the stack smashing issue for a while with nvclock. I finally was able to compile a version of nvclock 0.8b2 with the "-fno-stack-protector" cflag that works for me every time. I did this by running the configure script and then manually editing all of the Makefile's in the tree and adding "-fno-stack-protector" (without the quotes) to all of the CC= lines."
I haven't dealt with this kind of thing. I'll wait some time to do this. This is quite tiring...
-----------------------

Nike+ Sportband is a good device for tracking jogging, but unfortunately, Nike seems not interested to make a Linux driver. But we have an alternative user made driver, you can grab the driver, comsport, here. Besides I had to install a dependency, i encountered following error for another dependency:

"Consider adjusting the PKG_CONFIG_PATH environment variable if you installed software in a non-standard prefix." I really don't know what was the problem, but I googled the error message and found the problem was not for the program which designated by the error but the developer package for the program (the name of the package will be "theprogramname-dev").

Following instruction is taken from here. (I recommend to use aptitude than apt-get, and checkinstall than make install.)

The best way to solve your problem is:
sudo -s
apt-get update
apt-get install build-essential
apt-get install libusb++-dev
apt-get install libusb-dev
tar -xzf file.tar.gz
./configure
make
make install
now copy file 90-sportband.rules to /etc/udev/rules.d/
restart udev or reinit your pc.
now you have installed your driver.
The GUI needs Java Runtime, do:
apt-get install sun-java6-jre
You can run de GUI doing: java -jar file.jar

Disable auto launching, make VirtualBox work with iTunes 9.2

Disable applications from launching automatically:

On Ubuntu 10.04, this setting can be changed in the preference window of Nautilus. See the Media tab.

Make VirtualBox work with iTunes 9.2:

ps. How to show all the USB devices dimmed in grey

Enable VT-x/AMD-v in settings of Virtual Machine. Reboot, enter the BIOS, find Virtualization tab, enable Virtualization extension. Then it will Boot Then, TURN OFF the PC - Turn on again. (Don't reboot, turn the PC off. I don't know what is exactly different, but rebooting doesn't seem like turn on the virtualization function.)

Now launch VirtualBox and run the virtual machine. Go to /home/user_name/.VirtualBox/Machines/virtual_machine_name/Logs, then open VBox.log file. Search the word "VT-x". See if it reads as activated. If it is successfully enabled, you're good to go with iTunes 9.2!
If you don't have virtualization function in your BIOS, then it seems worth to install VMWare. But it seemed quite complicated to install it on Linux.

information from Ubuntu forum