Okay, so I'm pretty much going to give you a heads up on how to complete the Pokedex via the glitches in Pokémon Yellow. The natural maximum number is 129. Just to get you the idea, here are the Pokémon unavailable:
Weedle, Kakuna, Beedrill, Ekans, Arbok, Raichu, Meowth, Persian, Koffing, Weezing, Jynx, Electabuzz, Magmar, Mew
Pokémon you need to make a choice between:
Hitmonlee/Hitmonchan
Eevee-->Vaporeon/Jolteon/Flareon
Omanyte--->Omastar/Kabuto-->Kabutops
Finally, Trade Evolutions (skipping Machamp because you can naturally get one through an in-game trade):
Kadabra-->Alakazam
Graveler-->Golem
Haunter-->Gengar
151-14-5-3=129. If you understand how to use the Mew glitch, then make that 130 max. Well, I'll give you a rundown on the easiest methods of getting all of them:
1. Gengar: Trainer-Fly off either the second or third Lass of Route 3 (the third Lass uses Jigglypuff)--the earliest Trainer-Fly in Yellow is the third Bug Catcher in Viridian Forest.
2. Mew: Trainer-Fly off of the Super Nerd defending the fossils.
3. Make sure to pick up the Dome Fossil--very important.
4. When you pick up the Eevee in Celadon City, be sure to give it either the Water Stone or the Thunder Stone (not Fire Stone--you'll see why).
5. Trainer-Fly after you defeat Jessie and James at the top of Pokémon Tower to catch Koffing; evolve it all the way into Weezing.
6. Pick up either the Hitmonlee or Hitmonchan in the Fighting Dojo (doesn't matter).
7. Catch an Omastar off of Gary in Silph Co.
8. Catch an Omanyte off the Channeler in the far-left room in Saffron gym.
9. On Route 16, catch Hitmonchan off the very first Biker upon entering through the gate.
10.On Route 17, catch Electabuzz off the Biker with the lone Muk on the lefthand side (before the path branches off yet again).
11.On Route 17, on the righthand side, catch a Hitmonlee off the Biker/Cue Ball with just one Pokémon.
12.On Route 18, catch an Arbok off the Bird Keeper on the far left above the patch of grass.
13.On Route 18, catch a Magmar off the Bird Keeper with the Dodrio.
14.On Route 18, catch a Weedle off the Lv. 80 Snorlax that spawns from the trade request inside the gate (requires two Trainer-Flies to be active simultaneously).
15.Evolve Weedle all the way into Beedrill.
16.Catch Flareon off of Koga.
17.On Route 15, catch a Golem off the girl up on the plateau--need to use Cut.
18.On Route 12, catch a Jynx off a Lv. 35 Seadra (may require multiple tries in order to pull off).
19.On Route 11, catch an Alakazam off the Lv. 80 Clefable that spawns from the trade request inside the gate (again, requires two Trainer-Flies to be active simultaneously.
20.In Power Plant, catch a Raichu off one of the Electrode (may require multiple tries in order to pull off).
21.Hand the Dome Fossil at Pokémon Lab on Cinnabar Island for a Kabuto, then evolve it.
22.In Cinnabar Gym, catch a Meowth off the fifth trainer inside, and evolve it.
23.In Victory Road 2F, catch an Ekans off the Juggler with the lone Mr. Mime.
24.In Victory Road 3F, catch an Eevee off the female trainer on the plateau, and evolve it into the remaining Eevee evolution (either Vaporeon or Jolteon, depending on who you need).
And that's pretty much all you need to do to complete your Pokedex in Pokémon Yellow version--without trading. Everything else not listed on here can be caught and trained in the wild. Though if you need some assistance, I can recommend you to this site--especially useful in Red/Blue, btw:
http://puu.sh/257S.
You're welcome.