I'm using rt61 card on kubuntu, using serialmonkey driver and encrytion is turned off for now.
The Motherboard is MSI K8MM3 which has via k8m800+VT8237R/8237R Plus Chipset

Here's my problem, I start up kubuntu, then view my router status on another machine. Half way through the boot process it connects, but by the time it gets to the boot screen it disconnects again.

I think it might be something to do with an irq problem. Here's the output from /var/log/message:

pr 1 08:45:13 lounge hpiod: 1.6.9 accepting connections at 2208...
Apr 1 08:45:14 lounge kernel: [17179645.132000] ACPI: PCI Interrupt 0000:01:00.0[A] -> GSI 16 (level, low) -> IRQ 185
Apr 1 08:45:14 lounge kernel: [17179645.132000] PCI: Via IRQ fixup for 0000:01:00.0, from 10 to 9
Apr 1 08:45:14 lounge kernel: [17179645.136000] [drm] Initialized via 2.7.4 20051116 on minor 0
Apr 1 08:45:14 lounge kernel: [17179645.176000] agpgart: Found an AGP 3.0 compliant device at 0000:00:00.0.
Apr 1 08:45:14 lounge kernel: [17179645.176000] agpgart: Xorg tried to set rate=x12. Setting to AGP3 x8 mode.
Apr 1 08:45:14 lounge kernel: [17179645.176000] agpgart: Putting AGP V3 device at 0000:00:00.0 into 8x mode
Apr 1 08:45:14 lounge kernel: [17179645.176000] agpgart: Putting AGP V3 device at 0000:01:00.0 into 8x mode
Apr 1 08:45:15 lounge kernel: [17179646.844000] apm: BIOS version 1.2 Flags 0x07 (Driver version 1.16ac)
Apr 1 08:45:15 lounge kernel: [17179646.844000] apm: overridden by ACPI.
Apr 1 08:45:22 lounge kernel: [17179653.388000] <c01499a4> __report_bad_irq+0x24/0x80 <c0149a9d> note_interrupt+0x9d/0x270
Apr 1 08:45:22 lounge kernel: [17179653.388000] <dc9ea74d> RTMPIsr+0x16d/0x1b0 [rt61] <c0149323> handle_IRQ_event+0x33/0x60
Apr 1 08:45:22 lounge kernel: [17179653.388000] <c0149448> __do_IRQ+0xf8/0x110 <c0105c89> do_IRQ+0x19/0x30
Apr 1 08:45:22 lounge kernel: [17179653.388000] <c010408a> common_interrupt+0x1a/0x20
Apr 1 08:45:28 lounge kernel: [17179659.612000] Bluetooth: Core ver 2.8
Apr 1 08:45:28 lounge kernel: [17179659.612000] NET: Registered protocol family 31
Apr 1 08:45:28 lounge kernel: [17179659.612000] Bluetooth: HCI device and connection manager initialized
Apr 1 08:45:28 lounge kernel: [17179659.612000] Bluetooth: HCI socket layer initialized
Apr 1 08:45:28 lounge kernel: [17179659.628000] Bluetooth: L2CAP ver 2.8
Apr 1 08:45:28 lounge kernel: [17179659.628000] Bluetooth: L2CAP socket layer initialized
Apr 1 08:45:28 lounge kernel: [17179659.640000] Bluetooth: RFCOMM socket layer initialized
Apr 1 08:45:28 lounge kernel: [17179659.640000] Bluetooth: RFCOMM TTY layer initialized

Is there anything I can do to fix this?

Still no luck, but I am able to get the card working under recovery mode. In the terminal I can ping to my hearts content. I did try removing the card and trying another pci slot, but no luck there.

I solved the problem, or at the least found a viable work around. I'm posting my findings just in case someone else finds themself in the same predicament and has to spend their weekend messing with the wireless card.

First off I tried adding irqpoll to the default kernel line in /boot/grub/menu.lst/. It now reads:

/boot/vmlinuz-2.6.17-11-generic root=/dev/sda3 ro irqpoll quiet

This kept the wireless card working after the login screen (hooray), but had the negative effect of causing the login screen to hang for about 2 to 3 minutes before the user and password boxes appeared. It even took a while before I could access a terminal screen by pressing ctr +alt and f1. After playing with xorg.conf for a while believed that it was the via chipset that was causing the problems.

Googling the web, I found a bug report that stated adding the option irqdisable to xorg addressed the problem of xorg hanging for a few minutes. The section for the onboard via graphics now reads:

Section "Device"
Identifier "VIA Technologies, Inc. S3 Unichrome Pro VGA Adapter"
Driver "via"
BusID "PCI:1:0:0"
Option "DisableIRQ" "true"
EndSection

After that change the system boots quickly into xorg and there's no problems with the card. All I need do now is setup wpa encryption, but I think I will save that for another day.