Here is a first draft of my "old school" style skills for my new Microlite20-Old School Style Edition (now tentatively entitled "For Gold & Glory"). As you can see, the rules are fairly close to how Microlite74 handled skills, except that instead of basing any rolls the GM might call for off of level for tasks related to the characters class or level/2 for tasks not related to the character's class, the rolls are based on the character's skill rank in the appropriate skill.
Each class has one skill directly associated with it (physical for Fighters, knowledge for Magic-Users, and Communication for Clerics) which gets a +3 skill bonus. The player can freely select a second class skill -- this makes creating "subclasses" easy. Want a leader-of-men fighter, take Communication as your second class skill. Want a sneaky Magic-User, take Subterfuge as your second class skill. Etc. The player then selects two of the remaining three skills as secondary skills. The remaining skill is the character's minor skill. This allows for quite a bit of character customization without a lot of detailed rules.
While there are skills in For Gold & Glory, they are not used the way they are in most modern games. Instead of saying “I make my (name of skill) roll,” players are expected to think like adventurers, tell the GM what they are doing and the GM decides if it will succeed in the situation. If the GM decides a random success chance is truly needed, then and only then will a skill roll be made.
There are just five skills in For Gold and Glory: Communication, Knowledge, Physical, Subterfuge, and Survival. Each class has a class specific major class skill listed in the class description and a minor class skill of the player’s selection. A character gets a +3 class bonus to his major class skill. The player then selects two of the remaining three skills as secondary skills. The remaining skill is a minor skill. A player’s skill rank is:
Class Skill Rank = level + any bonuses due to class or race
Secondary Skill Rank = (level/2, rounded down) + any bonuses due to class or race.
Minor Skill Rank = (level/4, rounded down) + any bonuses due to class or race
When the GM calls for a skill roll, he will declare which stat the skill roll falls under and the player will make a skill roll.
Skill roll = 1d20 + skill rank + stat bonus + GM declared situational modifiers (if any).
Roll higher than the GM assigned Difficulty Class to succeed. Unless the GM rules otherwise, a natural roll of 20 always succeeds.