Please Help...upgrade options on older PII 266mhz

I have a question and I'm sure this is asked all the time but I'm getting a hand-me down dell optiplex that I wanted to network to my amd k6 III machine...The thing is this dell is a pentium II 266mhz machine and I wanted to know if I could swap in a pentium II 450mhz or maybe a celeron 450mhz or higher without having to change out everything else (mainly the motherboard)...I don't want to get into a lot of expese since it will be strictly a internet machine...probably more for just tinkering around than anything else but I noticed that pII cpus aren't to badly priced with the p3 out p4 being out. But I do understand that the 440LX chipset may be holding me back...And from looking on dells site they say nothing to the effect that their flash bios update will support more processors but it may but they don't say that explicitly...I included the specs from their site...I'm not really familiar with the intel stuff as much as amd but since I got this system at a good price I might as well do something with it. That's assuming that I don't need a motherboard swap...I'd appreciate any insights as to my options are if there are any related to cpu here...

actual specs below this particular unit is a 266mhz

General

Microprocessor type
Intel® Pentium® II microprocessor with MMX™ technology

Microprocessor speeds
233, 266, 300, or 333 MHz

Internal cache
32 KB (16-KB data cache, 16-KB instruction cache)

L2 cache memory
512-KB pipeline burst, 4-way set-associative, write-back SRAM

Math coprocessor
internal to the microprocessor

Microprocessor slot
1



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System Information

System chip set
Intel 82440LX PCI/AGP

Data bus width
64 bits

Address bus width
32 bits

DMA channels
8

Interrupt levels
15

Flash EPROM (BIOS)
2 Mb

System clock
66 MHz (matches external processor speed)



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Expansion Bus

Bus type
PCI (2.1-compliant) and ISA

Bus speeds
PCI: 33 MHz
ISA: 8.33 MHz

PCI expansion-card connectors:


Low-profile chassis
2 (1 PCI connector and 1 ISA connector share an expansion-card slot)

Midsize chassis
3 (1 PCI connector shares a card-slot opening with an ISA connector)

Mini tower chassis
5 (2 PCI connectors share card-slot openings with ISA connectors)

ISA expansion-card connectors:


Low-profile chassis
2 (1 ISA connector and 1 PCI connector share an expansion-card slot)

Midsize chassis
3 (1 ISA connector shares a card-slot opening with a PCI connector)

Mini tower chassis
4 (2 ISA connectors share card-slot openings with PCI connectors)



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NIC

NIC
integrated (on standard system board) or optional on EM system board; 3Com® PCI 3C905 network controller, operating at 10 or 100 Mbps



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Memory

Architecture
64-bit (non-ECC) or 72-bit (ECC), noninterleaved

DIMM sockets
3

DIMM capacities
16-, 32-, 64-, and 128-MB ECC or non-ECC SDRAM

Minimum RAM
16 MB

Maximum RAM
384 MB

BIOS address
F0000h

I have PII 300 and recently upgraded from 64mb of RAM to 256, and the performance increase is very noticeable. since RAm is so cheap, if you have 32 or 64 meg of RAM this is probably the cheapest, easiest (just stick 'em in the MB and go), and most effective upgrade path. Especially if the machine is mostly used for internet browsing and common office apps, more CPU power won't be as much help as more memory. Assuming you have 64 or 32 mb right now.

I believe this product may help you.

http://208.55.249.79/PL-iP3/index.html