How does metaphase i differ from metaphase ii?

Metaphase refers to the (relatively) brief moment when chromosomes are aligned in the middle of a dividing cell. During specialized cells divide to create gametes (sex cells). There are two divisions during meiosis so there are two metaphases.
During metaphase I sister chromatids are still connected forming the classic X-shaped double chromosome and they are aligned with their homologous partner (two Xs) that has the same genes.
After meiosis I homologous chromosomes are no longer in the same cell so metaphase II is the single file arrangement of sister chromatids in the middle.
In short Metaphase I is the separation of homologous chromosomes. Metaphase II is the separation of sister chromatids.
Here are two good animations that also help visualize the process. They may not be compatible on a mobile device.
http://highered.mcgraw-hill.com/olc/dl/120074/bio19.swf
http://highered.mcgraw-hill.com/olc/dl/120074/bio17.swf

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