To find the free space in an ASM disk :
select group_number, disk_number, name, failgroup, create_date, path, total_mb,free_mb from v$asm_disk;

To find the free space in an ASM diskgroup :
select name, group_number, name, type, state, total_mb, free_mb from v$asm_diskgroup;

To see the current ASM operations in Progress :
select group_number, operation, state, power, actual, sofar, est_work, est_rate, est_minutes from v$asm_operation;