- I for the moment found:
http://gparted.sourceforge.net/livecd.php
gparted live cd, but i am a bit scared to loose the data of my vista partition with it ...

is it the best, what other alternatives we have?

Out of those I've used, it's "the best" as in "clear and easy to use and works". Obviously you're responsible for taking backups of any important data, and should something go wrong there's nobody else to blame than you yourself if you didn't do it, but it's not like gparted is going to trash everything I've never lost anything by using it, and I've resized and moved both Linux and Windows partitions quite a few times. It's good practise to do one thing at a time (i.e. resize a partition, apply/write changes, then move a partition, apply changes, ...) in my experience, but apart from that just pay attention to what you're doing and you should be fine.

Remember: even though you probably don't hit any problems, you're the one who decides if backups are needed or not. Your post sounds like taking backups is a good idea anyway; if you are afraid of losing something, you shouldn't take chances, and if you are afraid of it now, it means you haven't taken any measures to prevent data loss in case of an accident. So go to a store, buy some DVDs or an external harddisk for a start, make backups of anything important in your Vista installation and then proceed. Probably you don't need the backup, but if you don't make it, you shouldn't worry about losing anything either (as it means you don't have anything important to make a backup of).

if you can partition your hard disk properly and install linux,then you'll never loose any data...

I would recommend first defragging the Vista partition. Then resize it in Vista, just in case Vista has done anything to it's version of the NTFS filesystem.

I did this once, but didn't defrag. Defragging would have moved data near the end of the partition toward the middle. The amount that vista would reduce it by wasn't enough. So after installing SuSE, I resized the Vista partition & the Linux partition and ended up needing to repair both filesystems. This wasn't hard to do, but you might want to avoid the headache.

You may also try freeware EASEUS Partition Master Home Edition which allows you to resize Vista without any data loss.

Also check

How to Shrink Vista Partition with Ease?

I was leary to use gparted on Vista as well.

Used Auslogics defragger(recommended in another thread) on Vista after cleaning out temp files and such with diskcleanup. Shrank partition with Vista's tool which still leaves the partition too big.

Finished shrinking the partition with Easeus successfully. Easeus also moved a restore partition safely.

How is this supposed to be helpful??? For this to be useful, you would need---as a minimum--to suggest HOW to do the partitioning.

The basic steps:
1. backup all important data
2. de-fragment, if necessary
3. re-size partitions as needed---use whatever works--eg GParted
4. make new partitions and install Linux

Did I mention "backup"?---Ah, yes....

I had 2 partitions when I bought my hp laptop:
on c: was the main vista system
on d: (smaller partition, about 10GB) the recovery system
(as hp didn't provide vista install cd)
I successfully resized the main partition, moved the
second windows partition next to the newly resized partition
with PartedImage live (http://partedmagic.com/)

Here are the steps I followed:
1. I installed the live PartedImage on a usb flash key
2. I booted with it
3. I launched gparted
it has a graphical view of the disk with all the partitions
4. I resized the main vista partition from 280 or something GB to
70GB
5. I moved the second partition (vista recovery) next to the newly
resized partition
6. I quit gparted and rebooted in windows vista
on boot, vista ran its check disk utility and it displayed
an ok message at the end and I was able to get to vista desktop
normally
7. I rebooted with any live linux to create new linux partition(s) in the
new available free space (using fdisk)
8. I rebooted with a linux install cd (slackware12.2 dvd) and
installed linux on the partition created in step 7

I can give more details on how I installed a multiple linux system
on my usb stick.
But you can also download the iso file of pmagic, burn it to a cd and
do the operations described above from the cd.