It depends on the context. If you spell just simple пиши, it will mean "write", an imperative, as dm1795 has already said. But you can put it to the end of the letter, so it will mean "Write me". But be carefull, cause it won't be formal as well as it won't be very polite. (It won't be rude, but it will be a little bit impolite)
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Date: 2007-06-12 01:42 pm (UTC)no subject
Date: 2007-06-12 02:06 pm (UTC)no subject
Date: 2007-06-12 02:57 pm (UTC)no subject
Date: 2007-06-12 04:57 pm (UTC)http://multitran.ru/c/m.exe?l1=1&l2=2&HL=2&EXT=0&s=%EF%E8%F8%E8
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Date: 2007-06-14 07:23 am (UTC)no subject
Date: 2007-06-13 06:36 pm (UTC)no subject
Date: 2007-06-13 08:14 pm (UTC)I would say that it's impolite, it's just informal.
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Date: 2007-06-13 08:46 pm (UTC)But OK I agree...you CAN use it ;)
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Date: 2007-06-14 01:24 am (UTC)If you using "Вы", you can say "Пишите мне".
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Date: 2007-06-14 05:36 am (UTC)(i'm russian)
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Date: 2007-06-14 06:12 pm (UTC)no subject
Date: 2007-06-15 01:22 pm (UTC)I use http://lingvo.yandex.ru (http://lingvo.yandex.ru), it's good for idioms too.