In most respects this spell mimics the ‘wings’ attribute that some races have. Most importantly you can fly over water and lava, but a few areas will also let you float up to things or over obstacles. Since things like falling and height are borderline random in how they’re enforced, your mileage will vary. This spell is usually better than water walking.

The in game help reads:

No saving throw.
Casting time: 4 rounds.
Type of spell: neutral spell.
Affecting stats: wis.
Cast type: control.
Spell point cost: 24.
This spell dates back to the origin of practiced magic. One of the earliest
tests of magical power, was the ability to magically lift and support objects
without any assistance except from the magic itself. By keeping only a minor
amount of concentration, a caster can make himself float off of the ground.
This helps him avoid any perils that might come from having contact with the
ground, such as floating over water.