If you have a Sony Vaio N505SN and are running Linux on it, why don't you, too, write an account of how you got things working? The Linux Laptop Page can always use more documentation!
At my (now) previous workplace I got the computer-equivalent of sex: the sleekest and most sexy laptop on this planet. I installed Redhat 6.2 on it.
I initially planned to make this a dual-boot machine, but later decided that I'd rather make it a Linux-only machine. However, if you decide to make it a dual-boot machine with Win98 (the only one I tried) then be sure to either keep the original install and use partition magic or something similar to resize the original partition, or create new partitions and keep the first one free to install Windows on it.
Eventually I decided to give this a try, and the restore doesn't ruin your existing partitions (as long as you left the first partition for Windows large enough) no matter what dire warnings the restore program displays. Windows98 got put back on from the recovery CD cleanly, and it all seemed to work. I got so fed up with it that I reclaimed the partition for Linux, though.
When repartitioning the harddrive, make sure to have a partition at the end of the disk, about 100MB for the 64MB model, 200MB for machines with 128MB. This partition should have partition type a0, "IBM Thinkpad hibernation", and is used by the laptop to suspend to disk.
I installed Redhat from CD, which turned out to be the easiest option. Network-install might work if you find a redhat install bootdisk that supports your PCMCIA networkccard. Anyway, the CD boots fine, as long as you boot it with the ide2=0x180,0x386 option at the lilo bootprompt to enable the PCMCIA cdrom drive. After that installation is pretty standard.
The Vaio uses a Neomagic graphics chipset, which is supported by XFree86 and should be autodetected at install. You'll probably want to use 1024x786 with 16bit colour as your working resolution. The input device behaves like a standard PS/2 mouse, and you should enable emulate3buttons.
Sound is the tricky bit: the Vaio uses a Yamaha chipset, which isn't supported by Linux. While it may be possible to get Soundblaster16 emulation to work, the quality isn't optimal. The best solution is to get the OSS sounddrivers, which cost $30 for the Linux version. You can download a trial version and get your license key online later. Well worth the money, imho.
If you hear a loud beeping noise when running soundon, then you haven't read the OSS manual. The Vaio microphone tends to feedback, causing this incredible beeping, but this can easily be fixed by running ossmix mic 0 followed by savemixer from the OSS install directory. This disables the microphone and presto, high quality sound. I found the quality of the tiny builtin mono speaker quite good, actually, although I wouldon't use it for hifi purposes...
PCMCIA should work out of the box, but you'll probably compile a new kernel after install, and that'll probably be a newer version than the one that comes with RedHat 6.2. You'll need to get the PCMCIA package, I used pcmcia-cs-3.1.15.tar.gz. This installed flawlessly after the new kernel compiled, and supported my 3Com megahertz network card.
Linux 2.2 kernels don't have (adequate) support for USB, but you can easily apply a backpatch from The Linux USB project to the 2.2.14 or 2.2.15 kernel. Using the Alternate UHCI drivers works fine for me, and this Vaio powers a Creative Webcam all day now. Now, to get it to work with *two* cameras...
The floppy drive shouldn't be too much of a problem, either, I found that linux USB deals rather well with this one. I just compiled scsi support as modules, ditto for the usb-storage (mass storage driver), insmod and there you go, floppy is now sd[a-z]...
The best place to learn about this are of course the FAQs, but some important tips are:
A good place to look for information is the Linux Laptop Page.