Ruby 505 479 474 442 439 426 chars
A first attempt. Have done it with IronRuby. I'm sure it can be improved, but I really should get some work done today!
p,q,r,s=(0..9),(0..2),(0..6),0
t=[*$<]
f=p.map{|a|g=0;r.map{|b|g+=2**b if t[6-b][a+1]==?#};g}
t.pop.split.map{|x|w,y=[15,51,306,562,23,561,113]["IOZTLSJ"=~/#{x[0]}/],x[1].to_i
l=q.map{|d|r.inject{|b,c|f[d+y]&(w>>(d*4)&15-c+1)>0?c:b}}.max
q.map{|b|f[b+y]|=w>>(b*4)&15-l}
r.map{i=f.inject{|a,b|a&b};f.map!{|a|b=i^(i-1);a=((a&~b)>>1)+(a&(b>>1))};s+=i>0?10:0}}
p.map{|a|r.map{|b|t[6-b][a+1]=f[a]&2**b>0??#:' '}}
puts t,s
Testing
cat test.txt | ruby tetris.rb
[ ]
[ ]
[ ]
[ ]
[# ###]
[# ### ]
[##### ####]
[==========]
10
Edit
Now using normal ruby. Got the walls output..
